[jujumantb]

Originally Posted by Sniper101

True, always 50:50...just do a mendelson table

X X
y Xy Xy

X XX XX

And congrats nyck

punnett squares are better for determining genotype probability comparing dominant and recessive alleles.
its easier to think of it like this: (juju's biology lesson for the day)
all male cells have an X and Y chromosome, when our jewels make sperm, each germ cell (again, containing one X and one Y) goes through gametogenesis to make 2 sperm each. one sperm ends up with the X and one has the Y. So in theory you have 50% X carrying sperm and 50% Y carrying sperm... whichever finds the egg first determines the sex.
its cool because the extra DNA in an X chromosome actually makes the X carrying sperm HEAVIER than the Y carrying sperm. using a centrifuge, they can actually seperate the X sperm from the Y sperm in a lab so, if you want, you can basically decide the gender of your kids by telling them which batch of sperm to shove into the moms vag.