Is there scientific evidence that animals have an innate/instinctual urge to reproduce? Is there scientific evidence that it is the same in humans? [more inside]
posted on Jul 11, 2007 - 45 answers

What is the evolutionary relevance of PMS?
posted on Jul 2, 2007 - 49 answers

Why do humans and animals(?) urinate from their sex organs? Are these two bodily functions in some way related? Are their examples of animals that pee & have sex with parts of their bodies that are spaced far apart? [more inside]
posted on Jul 22, 2006 - 32 answers

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