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“In terms of its dimensions, it’s clearly the right shape and everything,” Sara Rivers-Cofield told mental_floss.

There's no rule that regulates how animals obtain the necessary genetic material to reproduce—and as a result, there is a lot of weird animal sex going on out there.

It’s gross. It’s tender. It’s … lengthy.

Women and men in ancient cultures used a variety of unusual methods to prevent pregnancy, with differing levels of success (and hygiene).

How do you make people make more people?

All-female mole salamanders could grow back body parts 1.5 times faster than a related species that used sex to reproduce.

People who view their personality traits as fixed are more affected by romantic rejection, a Stanford study finds.

Scientists say over-the-counter sex pills are a waste of money at best.

A new study finds that king penguins look for mates with similar beak coloring.

They're not nearly as common as pop culture might lead you to believe.

Hint: there's no physical contact involved.