Gender

Sexes (or genders) are the divisions between different members of a species. The divisions are usually naturally evolved to biologically facilitate the combination of life processes for the creation of offspring.

Sex
Sexes are biological variations between different members of a species. These divisions are usually naturally evolved to biologically facilitate the combination of life processes for the creation of offspring.

In many humanoid species, and other lifeforms related to them by evolution, this involves a combination of two or more individuals' genetic material. It is also possible for members of certain species with compatible or related genetic structures to practice inter-species reproduction.

In many animal species, the female initiates the mating ritual. Captain Janeway reminded Tom Paris of this when they hyper-evolved into salamander-like species and produced offspring. 

Many species facilitate this bonding with some form of a wedding ceremony.

Variations in sexes
There are also various alien sexual makeups which consist of different constructs or combinations of sexes:


 * Androgynous : This refers to an individual (or species) which has neither male nor female functions. Species of this nature have uniform and identical sexual characteristics and functions for the creation of offspring. Although simpler lifeforms, like amoebae, simply divide their genetic material to procreate, more advanced lifeforms like Xindi-Insectoids are genderless and reproduce asexually.


 * The J'naii reproduce by recombining the genetic material of two individuals, but without assigning either of them a gender role in the sexual process.


 * Hermaphroditic : This refers to an individual (or species) such as the Tholians, which has two or more sexual characteristics or biological functions combined. Unlike the androgynous, hermaphrodites have the capability of being male or female during a sexual process, or undergoing a functional transformation from one gender to another.


 * Multiple sexes : Some species have more than two sexes, or different capacities are assumed by sexes not conforming to the pattern of male/female bonding which seems to be common throughout the galaxy.


 * Vissians require three separate sexes to reproduce: Male, Female, and a Cogenitor who serves as a catalyst for the fertility of the female.


 * Andorian marriages typically involve four partners and Bolian marriages are known to include co-spouses.


 * Species 8472 is composed of five different sexes, and Doctor Phlox believed Rigelians to have four or five genders.

Gender
"In spite of Human evolution, there are still some traits that are endemic to gender."
 * - Deanna Troi

Gender may refer to a cultural construction that often, but not always overlaps the biological division. However, the terms "sex" and "gender" are often used interchangeably (as in the quote immediately above).

Male and female gender
Many familiar races and cultures are based around the division between male and female, a two-sex system where the male adds a genetic seed to be combined with the female's genetic seed in a process called sexual reproduction. Many more advanced lifeforms still maintain such distinctions. When two members of the Q Continuum chose to practice two-party reproduction, they manifested themselves in such a manner. However, Q revealed a scornful attitude toward human females when he discovered Humans in the Delta Quadrant a century sooner than expected: "This is what happens when you put a woman in the Captain's chair!"

Worf once explained that it was his understanding that "in most Human families, the woman shares in the cooking."

William T. Riker referred to an Earth nursery rhyme, "What Are Little Boys Made Of?", which stated: "Girls are made from sugar and spice, boys are made from snips and snails... and puppy dog tails," to describe the "old-fashioned way of looking at the sexes" to the androgynous Soren. He later clarified that "physically, men are bigger, stronger" and that they "have different sexual organs". He also noted that "men can't bear young."

When Malcolm Reed was taken over by non-corporeal "wisps," he reminded a crewman that she was a female, and later told T'Pol that she was female, and that he wished to mate with her. This discussion suggests that these lifeforms no longer have genders. 

Transgender
Normatively male gender is assigned to the male sex and female gender to the female sex. Transgender is the general term relating to a variety of gender identity divergences from this norm.

During the wedding ceremony of William T. Riker and Deanna Troi, Data also welcomed the invited transgendered species. 

Background
Star Trek: The Original Series was widely known for being the first show to portray women (of different races, no less) working alongside men in service.

Kate Mulgrew as Captain Janeway was the first female lead actor of a Star Trek series. The first female Captain seen on Star Trek was the Saratoga captain seen in, played by Madge Sinclair. While Majel Barrett's character Number One may have been the first female first officer to appear in Star Trek, it was Nana Visitor's character, Kira Nerys, who was heralded in the media as being Star Trek's first female regular character to serve as first officer.