Snakes have two penises (aka hemipenes) that come in a diverse array of shapes and sizes. And they could owe it all to their lack of legs.

In high school biology, we learn that humans are born with either XX or XY chromosomes, and that a person’s internal and external sex organs match those chromosomes. It turns out, however, that sex isn’t that straightforward.

Hank lets us in on the meaning of life, at least from a biological perspective - it's reproduction, which answers the essential question of all organisms: how do I make more of myself? So, sex, how does it work?

Male birds have the largest genital diversity of any class of animals because their sex chromosomes make it easy to pass male-helping mutations down the...

Howcast - Learn how to recognize sexually transmitted disease symptoms from sexpert Jane Bogart in this Howcast video.

Howcast - Learn what sexually transmitted diseases you can get from oral sex from sexpert Jane Bogart in this Howcast video.

Howcast - Learn to recognize genital herpes symptoms from sexpert Jane Bogart in this Howcast video.

Howcast - Learn if non-genital herpes can cause genital herpes from sexpert Jane Bogart in this Howcast video.

Howcast - Fight the hormonal drop that occurs as you age with the following testosterone-boosting tips.

Meet Jeremy, a left-coiled snail, and discover the scientific quest to understand his rare genetic trait.

Just like Erikson's stages, Freud's Stages of Psychosexual Development is a popular tool in analysing human psychology and mental development. This video covers the important aspects of this popular and controversial theory consisting...

We delve into what it means to be transgender, as well as the differences between biological sex, gender identity and gender expression.

Expand your vocabulary with euphemisms! Euphemisms are an important part of the English language. Euphemisms are used when you want to avoid saying something that might sound unpleasant.

Throughout this series, we've learned all about the various systems of the human body. But how do humans make more humans? As a child might ask, where do babies come from? Suppress the immature giggles if you can, human reproduction is...