If you are pregnant with identical twins, it is pretty safe to say that if they are identical twins, they’ll be either girls or boys. Identical twins are always the same gender because the same fertilized egg develops them. That’s why they share the same genome.
Are you thinking, “Can identical twins be of different genders?”
Sometimes, identical twins may have different genders, which is a very rare event. Medically, this situation is called chimerism or mosaicism. It happens when an embryo splits into two zygotes with different chromosomes, determining the baby’s gender.
But, in most cases, that doesn’t happen. So, if your gynaecologist told you that you’re having twins, get ready to welcome either two boys or two girls!
Why Identical Twins Are Usually the Same Sex?
Now, let’s dig deep into biological concepts to understand why identical twins have the same gender. We all know that boys have XY chromosomes, and girls have XX chromosomes. Now, as told earlier, identical twins develop from the same fertilized eggs, and that’s why they have identical chromosomes and hence get the same gender.
In the medical term, identical twins are called monozygotic, which means they will have the same chromosomes and DNA. That’s why you’ll have a set of boys or girls (Boy/boy, girl/girl).
Now, if you are thinking about how the different genders are born twins, here’s what you need to know. Twins that are not identical are called Fraternal twins. They develop when two different sperms meet two different eggs (which usually happens). When both eggs get fertilized simultaneously, they develop two embryos, which develop two zygotes. Now, babies born from these zygotes may have different genders because their chromosomes and DNA are different. It is how fraternal twins are born, which are born on the same date but have different genders.
This type of twin is called dizygotic, the most common type. According to studies, approximately 70% of twin gestation is fraternal twins. If you’re giving birth to identical twins, know you are blessed beyond measure!
Why Identical Twins Can Be Different Genders
Well, it is quite possible to hear that someone is pregnant with identical twins, boy and girl. Though it rarely happens, it is possible. Babies born from the same egg can have different genders. There are some conditions in which identical twins can have different genders.
Identical twins are born from the same egg, which is why they have the same gene sequences. However, in some cases, genetic mutations can cause babies to have different genders. Such a situation is known as gonadal dysgenesis, in which changes occur in the gene that develops the genitalia.
In even rare cases, semi-identical twins are born. Researchers have only reported two cases of semi-identical twins because they develop when two sperm fertilize the same egg.
If you just conceived and curious about knowing what you’re expecting, here are five signs that you might be pregnant with twins. Check them out!
