How many sexes are there? [more inside]
posted on Jun 28, 2006 - 17 answers

Are there really such things as "scars on chromosomes" and "X vs. Y" 'wars' between the male- and female-determining genes? [more inside]
posted on May 8, 2005 - 15 answers

Is there a proven biological explanation why women live longer than men?
posted on Apr 9, 2005 - 24 answers

How did we evolve separate genders? I assume it happened pretty early on, since most animals have a male and female, but wouldn't it have had to happen to lots of things at once for it to actually work?
posted on Jun 6, 2004 - 7 answers