The twin phenomenon is nothing short of fascinating.

The mere fact that a mother conceives multiples is mind blowing by itself, but then you get a unique and delightful surprise when you find out that you gave birth to twins that don’t look alike at all – as in, zilch resemblance! Why and how? It would be interesting to know that the explanation may go beyond being fraternal twins.

Why are there twins that don’t look alike?

The National Human Genome Research Institute explains that some twins may not look exactly alike by looking into the two different types of twins namely, the monozygotic and dizygotic. Monozygotic twins are actually identical twins who come from one and the same embryo.

After fertilization, this embryo divides. Since they come from the same DNA, their genes are a hundred percent identical.

Dizygotic or fraternal twins, on the other hand, are twins from two eggs that get fertilized by two different sperm cells. This would mean that both siblings share some common DNA.

If, for example, these twins are the same gender, they will not look the same because they don’t share all of their genes. The fetuses have a different genetic constitution. It is also possible that they will be of different genders.

Biracial Twins: Twins that look nothing alike

Biracial Twins are otherwise called “mixed twins.” From a biological perspective, biracial twins are fraternal (dizygotic) twins. They are basically born to multiracial families who differ in various traits and racial features like skin color. This may also be a clear reason why some twins look nothing alike.

There is a small number of genes that are responsible for a human’s skin color. These gene variants (alleles) sets a code for the differences in the melanin within people’s skin.

Some have high frequencies of dark skin gene variants, while others have a high frequency of light skin gene variants. So, when parents of biracial twins are of mixed race, the combination of both light and dark skin gene variants are present.

There are a number of biracial twins who have been featured because of their extraordinary stories. Among these celebrated twins are Marcia and Millie Biggs who was featured by National Geographic on April 2018.

Marcia and Millie’s parents, Amanda Wanklin and Michael Biggs, gave birth to the fraternal twin girls on July 2006 who had some similar features but were very different in the color of their skin.

Marcia inherited her mom’s light brown hair and fair skin while her twin had black hair and brown skin like her father. Their mom Amanda is English, while their father Michael is Jamaican. The twins were definitely used to being asked if they really were twins!

Another story that is equally fascinating is that of fraternal twin sisters Lucy and Maria Aylmer. The twins are actually the youngest among the five siblings in the family. Find out more about their story in the video that follows.

According to statistical geneticist Alicia Martin, when a biracial couple has fraternal twins, their twins’ traits would depend on different things like where the ancestors of their parents are from, as well as the complexity of pigment genetics.

Superfetation: An unusual and rare type of twinning

Superfetation happens when a woman who is already pregnant, becomes pregnant again. If we look into this further, superfetation happens when ova from two different menstrual cycles are released, fertilized and then implanted in the woman’s uterus. In normal conditions this is not possible.

Once an ovum is implanted, hormones would stop the process of causing another ovulation, preventing the release of yet another egg. But in the case of superfetation, these norms aren’t really so. So, instead of just conceiving one baby, there can be a second fetus from the succeeding menstrual cycle.

But even if the fetuses develop at the same time, they differ when it comes to maturity because they may have been conceived days or weeks apart. But again, note that superfetation is a very rare occurrence.

Superfecundation: Twins with different fathers

Yet another reason why twins do not look similar is that they have different fathers. This is called superfecundation and can only happen to fraternal twins.

Specifically, when a woman’s eggs are fertilized by sperm from different men from different incidences of sexual intercourse, superfecundation or heteropaternal superfecundation happens. Paternity testing will reveal who the biological fathers of the twins are.

Another explanation as to how superfecundation happens is related to fertility treatments. An example of this is the case of Dutch twins Koen and Tuen Stuart. These twins are a result of IVF or in vitro fertilization. At the lab, there was quite a mixup where equipment was used twice, so another man’s sperm was mixed with the father’s.

Fact: Even identical twins don’t always look exactly alike

It has been proven that even identical twins will not look or act exactly alike. Although they develop from the same egg and sperm having the same DNA, there are environmental differences in how they develop which causes them to have obvious differences like their height or weight.

In the womb, one of the twins may have a better connection with the placenta so they get more nutrients compared to the other twin. Another thing that causes these differences is epigenetic. This means that each twins’ genetic profiles may change or diverge as they age.

This happens especially when they spend more time apart.

Reasons that explain the phenomenon on twins that don’t look alike continue to leave a number of people baffled. The science and biology behind twinning can sometimes be difficult to comprehend but what is more important is understanding the circumstances as to how and why not all twins look alike has its benefits.

It is believed that having twins runs in the family and that twinning skips a generation. Although this might be commonly observed, the question as to how are twins made has much to do with what goes on in in the process of fertilization.

This means that it is possible for random mothers to give birth to twins. To understand the hows, whys and what nows, read on.

How do twins happen?

The Office on Women’s Health explains that twin births happen in two ways. Identical twins occur mostly by chance and come from one and the same fertilized egg. This means that this fertilized egg will split into two, which pretty much explains why identical twins have the exact same genes and look almost a hundred percent alike.

On the other hand, fraternal twins happen when two separate eggs are fertilized by two sperm cells. When more than one egg is released in a single cycle, this is called hyperovulation and is a genetic characteristic.

The process makes it possible to be passed from the mother to her child. This is why fraternal twins commonly tend to run in a number of families.

What factors will cause hyperovulation?

How and when an egg is released in a cycle is controlled by hormones during ovulation. Sometimes, however, hormones may signal the body to release more than one egg, which is not quite normal. Why does this happen?

This is influenced by a number of things like irregular usage of birth control pills or totally discontinuing taking them, using certain fertility drugs, breastfeeding, and obesity. Obesity (having a BMI that is more than 30) causes the production of higher levels of estrogen because the body has extra fat stored.

Other things that contribute to hyperovulation include genetics, family history, being pregnant over 30 years of age, being taller than the average, having a phytoestrogen-rich diet, and race. Apart from that, women from Africa have been noted to have a higher number of twin births compared to women from Asia.

Who is more likely to get pregnant with twins?

Based on the gathered data, women who are anywhere in their 30’s may be more likely to get pregnant with twins. This is because it is at this age that releasing more than one egg in a cycle is more rampant. This doesn’t happen much with those who are under their 20’s. After 35, however, the chances of getting pregnant with twins decreases.

Do fertility treatments increase the chances of having twins?

A report by the American Society for Reproductive Medicine shows that twin births happen in one out of 250 pregnancies. It is noted that this rate is higher in mothers who have had fertility treatments and because of such treatments, multiples occur in about one out of every three pregnancies.

Fertility treatments involve prescribing fertility drugs that are made to stimulate the ovaries. These drugs can cause several eggs to be released in one cycle. Take gonadotropins, for example.

A woman who takes has a 20% higher chance of getting pregnant with more than one baby. Clomid attributes to five to twelve percent, and IVF increases these chances anywhere between 20% to 40%.

So far, the only known fertility treatment that does not increase the rate of multiple pregnancies is intrauterine insemination. IUI is a method that injects sperm directly into the woman’s uterus through a syringe.

What are the complications when being pregnant with twins?

When a woman is pregnant with multiples, there are a number of risks and complications involved. One of which is that the babies may have a low birth weight (below 2,500 grams) which occurs in two-thirds of babies from multiple births. The main cause of this is because babies lack room for growing while in the uterus.

Another risk is that babies may have congenital defects. Such defects could be infant mortality, cerebral palsy, or other birth defects. Infant mortality has something to do with concerns associated with babies that are born prematurely.

Babies who are born less than 32 weeks are at most risk. Second, cerebral palsy is a disorder that affects a child’s motor skills and muscle movement. CP is mostly caused by brain damage that happens before or during a baby’s birth.

Prenatal care for mothers pregnant with twins

The moment you find out you are pregnant with multiples, the first thing to do is to choose a health practitioner. It may be best to see a perinatologist, otherwise known as a maternal-fetal medicine specialist (MFM). A perinatologist is an obstetrician who is a specialist in high-risk pregnancies.

Aside from choosing your health practitioner, expect that prenatal care for twins will need more ultrasounds and visits to the doctor. You may have five or more ultrasound examinations throughout your pregnancy. Once you are 18 weeks pregnant, you’ll need to have an ultrasound once a month until you give birth.

There are also some tests involved. One is a test for iron-deficiency anemia because iron is used up more quickly in twin pregnancies. Another test is the glucose screening test to monitor gestational diabetes. This test is usually taken when you are 24 and 28 weeks pregnant.

Your health professional will also be in a constant lookout for signs of preterm labor. They can go as far as recommending a fetal fibronectin test to rule this out. Fetal fibronectin is a certain protein found in the secretions from the vagina that is a sign that the body is preparing to give birth.

Now that you know how are twins made, you’ll know what to expect and you’d also understand why getting the best medical care for mothers who are pregnant with multiples is the top priority.

Not only does this lessen the occurrence of complications, but it also allows a mother’s family and friends to all the more be there for her for assistance, encouragement, and support.

Becoming a parent is a big step in every person’s life. The idea that you would care and nurture for someone for the rest of your life is both a blessing and a responsibility. And while some parents may be perfectly content with one new life to welcome, there are some (either through chance or design) who want to take more than one.

These are the people who look up the best way how to have twins.

Truthfully, twin births aren’t a sure thing. While there may be many factors that can affect your chances of conceiving twins, there isn’t a way to guarantee it. There are a few things that can tip the odds in your favor – some which we’ll be talking about here.

How To Have Twins: FAQs

Is there a medicine I can take to have twins?

There isn’t a medicine per se that can make you have twins, but there are ones that can increase the odds. One of the best examples of this is fertility drugs – in particular, Clomid. We’ve talked about Clomid twins previously, but here’s a brief rundown of why fertility drugs help:

• Fertility drugs increase your ovulation, which makes you potentially release more than one egg
• This extra egg can also potentially be fertilized by another sperm cell
• And can form into another fetus alongside your first egg cell

But again, this is merely increasing your chances, not guaranteeing them. And while fertility drugs can have an effect, the ovulation cycle of the woman is the primary factor in getting twins – and that’s not even counting the kind of twin that will develop.

If I conceive twins, will they be identical twins?

Not necessarily. There are many kinds of twins that you can have, and all of them have more or less an equal chance of happening. Twin births are amazing: Even if you’ve looked up how to conceive twins, your body (and your future kids) may surprise you!

With the variety of factors that can affect twin development and growth, you never really know until the OB orders an ultrasound.

Do twins run in the family?

Actually, yes! There have been some studies that point to the increased likelihood of having twins if you’re a twin yourself. We’ve also talked about this before, but the chances of you giving birth to twins are higher if you carry it from your mother’s side.

It’s why you also see news of twins that marry twins that go on to have twin births themselves – it’s in the genes! And again, this may increase your chances, but it doesn’t guarantee them.

Twin Births And You

There’s a certain mystique to having twins – after all, since they’re all so often unplanned, shouldn’t you sit and wait once the pregnancy test turns positive, and look forward to the two bouncing bundles of joy you’ll soon have?

Well, not exactly. Twin births can run into plenty of issues, some which start even before conception. This is mostly dependent on what kind of twin you’ll be having since that’s often decided shortly after conception. If you’re looking up how to get twins, you should be prepared for the effects that come from carrying twins.

Here are some of the things that you can expect from carrying twins:

• Double the fatigue. Your body will be providing for two growing babies – Expect to eat a lot more, sleep a lot more, and generally experience twice the side effects that you’d usually only associate with one child.
• Different issues. There are some issues in pregnancy that are unique to twin births, such as twin to twin transfusion syndrome. You should keep an eye out for these kinds of events, as they can be fatal to not only you but your children.
• A lot more visits to your doctor. Remember, there’s three of you now, not two! Your doctor will most likely request more check-ups and a closer eye on how your pregnancy develops as a result.
• More expenses. You’ve likely already prepared for this when you’ve thought about having a child – but don’t underestimate the typical costs you’ll get for twin babies! Pre-birth, post-birth, and them growing up are all going to be a little pricier than you’d think.
• Double the joy. There are few things quite like the first kick or flutter that you feel. Twin quickening is even more remarkable – and soon enough, you may be even able to differentiate one twin from the other one!

How to conceive twins – the natural way?

On the other hand, if you’re really wary about the idea of using drugs or the like for conceiving twins, you’ll need to make do with the natural way.

While it can still happen, the odds of it happening are quite low. Since the way that our cells multiply and divide (plus exactly how the ovulation cycle works for the mother,) it’s even more up to chance than it usually is.

However, it isn’t impossible.

We’ve all heard those stories about mothers who’ve just expected twins without really doing something about it – if it can happen to them, it can also happen to you! Stranger things have happened – right up to some quite bizarre twin births – so you prepare to be pleasantly surprised by the entire experience.

Whatever the results of your efforts trying to conceive might be, the important thing is that you will love and cherish the child you’ll have. Whether they be a twin or a single child, welcoming the newest member of your family with all the love and care they deserve is a must for any parent.

Each child deserves a household to that will cherish them as they grow up, and that’s an environment that only you can provide.

Do you know someone who swears by a specific method on how to have twins? Let us know in the comments below!

When you hear the term discordant twins, this means that the twins at birth show a distinct difference in size. Usually, the other twin’s weight is greater than 10%. This condition is common in identical twins but may also happen in fraternal twins.

To get properly oriented as to how this happens and how to manage this condition, there are essential things you need to know.

What Causes Twin Growth Discordance?

Twin growth discordance may happen in about 25% of twin pregnancies and can either be a weight discordance or size discordance. Weight discordance is a weight incongruence of more than 25% and is possibly associated with intrauterine growth restriction (IUGR) in the smaller twin.

Size discordance, on the other hand, is usually associated with anemia or can be a result of a twin-twin transfusion.

This condition is associated with a number of things like IUGR (intrauterine growth restriction) in the smaller twin, TTTS (twin-to-twin transfusion syndrome), or having a single umbilical artery (SUA) which is the absence of the right or left umbilical artery.

Discordance also happens when the placenta is unable to bring enough oxygen and nutrients to the growing baby. Other factors that influence this includes tobacco use, a viral infection, and if a mother does not have any prenatal care at all.

How are discordant twins diagnosed?

Growth discordance can be estimated by measuring the crown-rump length at or before 12 weeks of gestation. During the second and third trimesters, however, ultrasound measures are best used to estimate fetal weight and the degree of birth weight discordance.

Ultrasound examinations may be done in three different modalities:

1. Two-dimensional (2D) Ultrasound Examinations will measure the fetal growth of both twins. It will also identify chronicity, as well as problems when it comes to the umbilical cord, TTT, and congenital abnormalities.
2. The Doppler ultrasound will detect an abnormality when it comes to the patterns of blood flow in the fetal and placental circulation.
3. A three-dimensional (3D) ultrasound is used to assess the placenta as to its surface, volume, and blood flow.

What should I expect in delivery?

The American Journal and Obstetrics & Gynecology states that there are three relevant combinations of fetal presentations when it comes to twin pregnancies in labor. These are vertex-vertex (both of the twins’ heads are down), vertex-nonvertex (one of twins’ head is down, while the other is in a breech position), and both non-vertex, where both twins are in breech.

The manner of delivery will be dependent on how twin A is presented. When twin A is vertex, it is possible to have a vaginal delivery, a planned cesarean section delivery, or combined (both vaginal and c-section).

A combined delivery is done when complications arise like a cord prolapse, placental abruption, fetal distress, or malpresentation of the second twin. Active management during the second stage of delivery involves maternal pushing, amniotomy (artificial rupture of membranes), and oxytocin administration.

In planned vaginal deliveries, standard protocols will be applied. This includes intravenous access, continuous fetal monitoring throughout the duration of labor, having sufficient nursing available, anesthesiology and pediatric support, ultrasound exam, and being ready to perform a cesarean delivery if needed.

What are the outcomes of a severe discordant fetal growth?

If the discrepancy is over 20%, there is a high possibility of the smaller twin to have adverse perinatal outcomes. This includes perinatal death (stillbirth), birth asphyxia, respiratory distress syndrome, neonatal infection, and birth trauma. In the case that the baby is born alive, there will be severe problems after birth.

The larger twin, on the other hand, may have a high risk of acute respiratory difficulty after birth. But aside from that, there will be fewer complications. In addition, they may be born prematurely. A C-section may also be induced to remove the twins from the mother’s womb before natural labor.

Twin pregnancies with discordant twins are at higher risk of prenatal complications and have a less favorable perinatal result. This is why early detection is most important for closer observation and well-timed delivery. Try to find out more about discordant fetal growth from your healthcare professional.

If you’re an expecting mother who’s just gotten the good news that you’ll be having twins, then congratulations! Twins are quite a joy (aside from being a surprise), so you’ll want to find out as much as you can about them.

In your twin ultrasound, one of the questions that you might have is: “What is the difference when it comes to identical vs fraternal twins?”

There’s a rather exciting story as to why this phenomenon even happens in the first place – and we can walk you through it right now!

Twin Babies: Identical twins vs fraternal twins

As parents of twins, to understand the difference between the two, you need to have a short background on what makes twins happen in the first place. There are plenty of factors that influence twin behavior and growth, such as:

• The kind of medicine you take,
• Your family history,
• How your body develops,
• Ethnicity, age, and physical condition,
• Sheer luck

Truthfully, while some factors can influence the chances of you having twins, the actual possibility of it is very much in the air. But once your body does start to shift in that direction during your pregnancy, then comes the critical step that makes the difference between identical and fraternal twins: the embryo.

What happens in the embryo

The embryo is what’s formed and attaches to the uterus after fertilization – or when the egg cell meets the sperm cell. It is developed from a zygote – the immediate aftermath of those two sex cells meeting during intercourse.

Basically, you can think of an embryo as the foundation of what is to be a human being.

Now, here’s how it gets tricky. Your chances of getting either identical or fraternal twins actually don’t wholly rely on how the embryo (or embryos, in this case) behave. That’s because before fertilization even happens, your chances of deciding twins could already be determined.

This difference in the stages of conception to birth is what makes the difference between monozygotic and dizygotic twins.

Monozygotic twins: Identical Twins

Let’s back up a bit in the stages of pregnancy and go all the way to the actual moment of fertilization. When your egg cell was successfully fertilized, it formed a zygote that starts to make its journey to attach to your uterus. This is what happens in every pregnancy, and is critical for your future baby’s survival and development.

However, once it becomes an embryo, there is the chance of it splitting into two. This forms two copies of the same embryo, which then go onwards to develop into two, identical twins.

They may or may not share the same amniotic sac depending on their development, but otherwise, they are counted (concerning your cells) as one and the same.

Monozygotic twins share the same DNA and have the same gender when they are born. They may or may not look the same (especially if something called Twin to Twin Transfusion Syndrome – something that affects only identical twins) but factors such as time, environment, and their general life experiences can change that.

Dizygotic twins: Fraternal Twins

On the other hand, we need to look back even farther to see how fraternal twins are formed: specifically, up to the time of your ovulation. A typical woman will usually only release one egg cell during ovulation, and that single egg cell is then fertilized, forms a zygote, then grows into an embryo.

However, either due to the influence of genetics or medicine, a woman can release two egg cells at once, which are then fertilized by two separate sperm cells from the father.

These two egg cells develop into embryos of their own – fundamentally different children, with their own DNA, placenta, amniotic sac, and other parts. They attach to your uterus and grow into babies.

Dizygotic twins are two separate children that happened to be born at the same time – which explains why despite their identical dates of birth, fraternal twins may be different genders, have different DNA, and essentially act and look differently from one another.

However, they are still genetic descendants of both the mother and the father.

In summation…

To put it briefly, here’s the critical difference:

Identical (or monozygotic) twins follow the same steps as a routine pregnancy, with the only difference that the embryo formed splits into two.

Fraternal (or dizygotic) twins are formed from two egg cells fertilized by two different sperm cells, which then develop as a routine pregnancy.

Your chances of having either kind of twin will depend on a variety of factors, and it’s often quite hard to be entirely sure which ones will affect the type of twin pregnancy that you have. If you think you’re having twins, or wish to know what kind of twins you’ll be having, the best step would be to call your doctor.

While twins ultrasounds can somewhat reasonably determine the type of twins that you’re having, a DNA test is the only sure way to find out.

There are also different health hazards that are unique to these twin types. Again, asking your doctor and regularly consulting with them during your twin pregnancy can go a long way in assuaging any kind of fear or worry you might have.

If you want to learn more, here’s a video about twin development that you might want to take a look at.

And whether or not your future loved ones are identical or fraternal, the important thing is that you still recognize them as two children that have their own quirks, personalities, and foibles!

Loving your children is the standard for any parent, and whether or not how they were formed shouldn’t be a factor in that kind of love.

If you’ve loved this piece on the difference of identical vs fraternal twins, please leave a comment below.