Star Trek: Enterprise - Season 2 - Eps 22: Cogenitor
The Enterprise crew makes first contact with the Vissians, a species with three genders. Trip meets one of the species' third gender, known as Cogenitor, and learns how badly Vissians treat all Cogenitors. Trip attempts to help the Cogenitor, even though it interferes with Vissian culture.
About Star Trek: Enterprise

Title: Star Trek: Enterprise
First Air Date: 2001-09-26
Last Air Date: 2005-05-13
Status: Canceled
Rating: 7.569/10 (from 832 votes)
Language: EN
Seasons: 5
Total Episodes: 97
Network: UPN
Genres: Sci-Fi & Fantasy, Action & Adventure, Drama
Production Companies: Paramount Television, CBS Studios
Synopsis
During the mid-22nd century, a century before Captain Kirk's five-year mission, Jonathan Archer captains the United Earth ship Enterprise during the early years of Starfleet, leading up to the Earth-Romulan War and the formation of the Federation.
Cast

Scott Bakula
Jonathan Archer

Jolene Blalock
T'Pol

Connor Trinneer
Charles 'Trip' Tucker III

John Billingsley
Phlox

Dominic Keating
Malcolm Reed

Linda Park
Hoshi Sato

Anthony Montgomery
Travis Mayweather