-A curious adult from California
June 7, 2016
If humans had babies like Komodo dragons sometimes do, there'd be no need for sperm banks. Well, not unless mom wanted a little extra genetic variety from dad.
Normally, babies get half their DNA from mom and the other half from dad. But this isn’t always the case in nature.
When 2 x ½ is Not the Same as 1
To see why this is, let’s imagine that a woman had babies by doubling the DNA in her egg like a Komodo dragon sometimes does. And that she has AB blood type.
Turns out that none of her kids would be AB like her—they’d all be A or B. Let’s see how this works.
Scattered throughout your DNA are the genes that make up the instructions for making you. Each gene has the instructions for one small part of you.
A Virgin Birth Gives Males (For Komodo Dragons)
For most animals, whether you are genetically a boy or a girl is determined by which sex chromosomes you have.
In people this is decided by the X and the Y chromosome. Genetic males have an X and a Y and genetic females have two X’s.
This is why in people, dad determines the sex of the baby. Mom can only give an X, but dad can give an X or a Y. If baby gets X from mom and X from dad, then genetically the baby is a girl. If baby gets X from mom and Y from dad, then the baby is a boy.