When the top spotty fish in a tank disappears, the runner-up turns aggressive within minutes, rushing and nipping rivals ...

The genes of male and female placentas have marked differences in how they are expressed, according to a study by researchers at the National Institutes of Health (NIH) and other institutions.

If you've got a manual on USB ports or have watched any kind of video, you may have heard them referred to as Male or Female ports. Here's what that means.

Singer Katy Perry, CBS anchor Gayle King and other celebrity women will launch on Blue Origin's historic all-female astronaut crew this spring.

More say all-female social groups have a positive impact on women’s well-being than say this about all-male groups' impact on men.

Males and females of most parrot species look virtually identical. It takes a keen eye—and usually a lab test—to distinguish a male from a female.

Researchers have spotted an “extremely rare” green honeycreeper in Colombia that’s half female and half male. The bird’s plumage is divided directly down the middle, with blue feathers ...

The polar bear turned 17 and was gifted fish and raisins ice cakes, according to the Brookfield Zoo. The "paw-ty" didn't stop with the bear's birthday lunch.

Connor Stone’s fish could set a world record, North Carolina officials said. N.C. Division of Marine Fisheries A bright blue fish was caught off the coast of North Carolina — and it could set ...

“Genderqueer” and “nonbinary” are contemporary terms for people who don’t fit neatly into male or female categories. But acknowledging that not everyone fits neatly into those two groups ...