Why are there not more females than males if chromosome pairs split into gametes to be paired up again?

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This might not make much sense but I just read that gametes come from XX splitting to X and X and the same for XY into and X and a Y. Assuming these are evenly occurring then there are 75% X and only 25% Y, surely there’s more chance for XX pairs than XY occurring?

In: Biology

2 Answers

Anonymous 0 Comments

The 2 X’s that split can’t join with each other… plus, on the female side, in humans, there’s usually only 1 X allowed per month… and it joins with the 50/50 X-Y splits

Anonymous 0 Comments

The ovum is always X. The sperm are 50/50 X or Y. It’s the sperm that’s the deciding factor, hence 50/50 male to female result.