its a good question actually. cause yeah there's a 50/50 chance but who says that those chances would be so exact when it comes to it.
like 1 person in one part of the world has a boy, then another a girl until they're basically even.
with a 50/50 chance there's still the probability of the world pop having a disproportion of a single gender, but we don't and never do.
its like birth is linked globally somehow.