An odd species has been discovered under rare circumstances in the depths of the San Antón water mine in Seville province ...

With ear-like fins that flap gracefully through the water, the Dumbo octopus in this YouTube video looks like it waltzed ...

Not sure whether your leopard gecko is male or female? Thankfully, determining the sex of one of the adorable little lizards ...

So, is Imane Khelif male or female? Biologically, she might have traits typically associated with males. But socially, legally, and personally — she’s a woman.

Intensive exercise and sport changes the heart of an athlete. Research led by Amsterdam UMC shows that the hearts of female athletes have different characteristics than those of male athletes.

Read the paper: Maternal iron deficiency causes male-to-female sex reversal in mouse embryos. In mammals, including mice and humans, sex determination is controlled by genetics — that is, ...

Texas Senators passed a bill to define “male” and “female” in Texas law during a floor session that extended into the early morning Wednesday.

In recent years, many non-binary actors have often elected to run for awards in the male or female categories: Bella Ramsey, for instance, competed for best actress in various TV awards for their ...

Someone whose gender identity does not align with the sex they were assigned at birth and who may or may not go through gender transition. This is the opposite of cisgender, which describes people ...

World Boxing says Olympic champion Imane Khelif will not be allowed to fight in the female category at their competitions until she undergoes a mandatory sex test.