How can women deliver twins? how does the fertilisation differ from single child to twins/triplets?
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So there’s multiple possibilities when it comes to twins.
First thing is that women don’t only release one egg at a time during ovulation. They release quite a few. What then happens is when a sperm enters an egg the egg will then attach to the wall. This sends a signal to the body that “hey I’m pregnant, stop sending eggs”
But should two eggs be fertilized and then attached at the same time, then you end up with fraternal twins. Genetically different. Still siblings, but with different DNA.
With identical twins what happens is that when the fertilized egg goes through it’s very first mitosis, where the one cell splits into two, the egg might separate completely. So now there are two fertilized eggs. But they have identical DNA. This is how you get identical twins. They both came from the same egg and same sperm.
Triplets and quadruplets and all the others are some combination thereof.
I know some triplets where the two girls are genetically identical but their brother is a fraternal triplet.
You *can* have identical triplets, but you do have to start with identical quadruplets and one of them not take. So that’s a little sad.
There’s certain medications you can take that make all of these situations more likely. But it’s fairly rare to occur naturally.
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