Hermaphrodite

In biology, a hermaphrodite was an organism that had reproductive organs normally associated with both male and female sexes.

Despite their female-sounding voices, Alpha Centaurans were hermaphrodites and properly referred to as "it". Nevertheless, the Third Doctor generally used the masculine to refer to the Federation ambassador to Peladon. (TV: The Monster of Peladon)

Chelonians were hermaphrodites and all members could lay eggs. Despite this, Chelonians were referred to as males. (PROSE: The Crystal Bucephalus)

The Sloathes, (PROSE: Sky Pirates!) the Brascans (PROSE: Kursaal), and the Torcaldians (PROSE: The Ruins of Time) were also hermaphrodites.

There seemed to be no visual distinction between male or female Ood, which might suggest that they were hermaphrodites; however, when Donna called an Ood "it", the Tenth Doctor corrected her, saying she should call the Ood a "he". (TV: Planet of the Ood)