According to comments from Michael Taylor, the Colonials do not make an emphasis "of the distinction between hetero- and homosexual preferences. I tend to think that in this respect, at least, they’re a bit more enlightened than we are."
Gender Identity and Distinctions
No gender-based restrictions on occupation, either military or civilian, have been seen to exist in the Twelve Colonies, and Ronald Moore has indicated that there are none. However, males and females adhere to different standards in terms of clothing, makeup, ornamentation and hairstyling. One example has been seen of a transvestite, a man called Cerberus who wears "female" garb, jewelry and makeup; he is referred to as a "freak" by Joseph Adama (CAP: "Ghosts in the Machine").
In marriages between only one man and only one woman, there are examples of both partners retaining their surnames (ex. Anastasia Dualla and Lee Adama) and of the woman taking the surname of her husband (ex. Sharon Agathon and Karl Agathon). However, the common surname of the Willow group marriage derives from one of its female members, Desiree Willow. The standard practice for two-person homosexual marriages is unclear, as the only one shown so far is that between Samuel Adama and Larry, the latter of whom is only referred to by his first name. It is unknown whether the surname a person used before marriage is referred to as a "maiden name" by the Colonials.
A concept of "manliness" exists, as evidenced by William Adama's sayings "a man isn't a man until he wears the wings of a Viper pilot" and "a man takes responsibility for his actions". If an equivalent idea of "womanliness" as a strong attribute exists, it has not been referenced (TRS: "Miniseries", "Water").
Tauron boys are known to be considered men at the age of 13 and receive a Mark of Manhood. No equivalent tradition has been mentioned for girls, although women fulfill the same roles in Tauron society as men do (ex. Isabelle Adama as a Ha'la'tha resistance member, Kolibri as a Herac soldier, Ruth as a hitwoman, Fidelia Fazekas as the Guatrau) (CAP: "Gravedancing", "Dirteaters", "Here Be Dragons" and "Apotheosis").
In the Colonial military, the honorific "sir" is used for both female and male superiors; in civilian usage, "ma'am" is used for women and "sir" for men. This is highlighted when Captain Lee Adama addresses President Laura Roslin as "sir" and her aide Billy Keikeya addresses her as "ma'am" at the same meeting (TRS: "Bastille Day").
Relationships depicted in the series tend to be overwhelmingly heterosexual in nature. Amongst these relationships are:
- Relationships resulting in marriage:
- Saul Tigh and Ellen Tigh (2,000 years in the series' past, and again in series' present.)
- William Adama and Carolanne Adama (TRS: Miniseries, "A Day in the Life")
- Romo Lampkin and Faye Lampkin ("The Son Also Rises", "Sine Qua Non")
- Jurgen Belzen and Rika Belzen (TRS: "Razor")
- Sesha Abinell and Ray Abinell (TRS: "Sacrifice")
- Simon O'Neill and Giana O'Neill (TRS: "The Plan")
- Cally Tyrol neé Henderson and Galen Tyrol (TRS: "Lay Down Your Burdens, Part II")
- Kara Thrace and Samuel Anders (TRS: "Lay Down Your Burdens, Part II")
- Anastasia Dualla and Lee Adama (TRS: "Lay Down Your Burdens, Part II")
- Karl Agathon and Sharon Agathon (TRS: "Precipice")
- Relationships between consensual, unmarried persons:
- Galen Tyrol and Sharon Valerii
- Lee Adama and Kara Thrace (TRS: "Scar")
- William Adama and Laura Roslin ("A Disquiet Follows My Soul"; previously implied in "A Day in the Life, "Unfinished Business")
- William Adama and Jaycie McGavin (TRS: "Razor Flashbacks")
- Richard Adar and Laura Roslin (TRS: "Epiphanies")
- Samuel Anders and Tory Foster (TRS: "Crossroads, Part II") [Anders was presumed to be a widower, though his wife, Kara Thrace, was later discovered seemingly alive]
- Billy Keikeya and Anastasia Dualla
- Enzo and Louanne Katraine (TRS: "The Passage")
- Saul Tigh and Caprica-Six [Tigh was presumed to be a widower, though his wife, Ellen, was later discovered alive]
- Cavil and Sharon Valerii
- Felix Gaeta and "Sweet Eight"
- Sexual relationship between consensual adults while engaged in other sexual relationships:
- Gaius Baltar and various female conquests such as Sherry Bennett, Caprica Six, Gina Inviere, Number Three, Kara Thrace, Tory Foster, Playa Palacios, and an unidentified woman in the Miniseries. Baltar's ongoing relations with Virtual Six are difficult to define, but certainly involve a sexual aspect.
- Ellen Tigh and various men during her marriage to Saul Tigh (TRS: Miniseries, "Tigh Me Up, Tigh Me Down", "Occupation", "Precipice")
- Ellen Tigh and a Cavil Cylon to secure Saul Tigh's release from prison.
- Lee Adama and Kara Thrace cheat on their respective spouses before (TRS: "Unfinished Business") and after (TRS: "The Eye of Jupiter") getting married.
- Spec. Callandra Henderson with both Lt. Brendan Costanza and SCPO Galen Tyrol; the former unknowingly sired her child, while the latter married her and was presumed to be the child's father. Both relationships were violative of fraternization regulations and/or laws (TRS: "A Disquiet Follows My Soul").
- Sharon Valerii seduces Karl Agathon under the guise of Sharon Agathon, while the latter watches helplessly, bound and gagged in a commode closet (TRS: "Someone to Watch Over Me").
- Saul Tigh with Ellen Tigh upon her return to the Fleet, while he (having been presumed widowed) is cohabitating with Caprica-Six, who has become pregnant by him. Ellen recognizes that he has added to his sexual repertoire during her absence.
The revelation of the Cain-Inviere relationship does not seem to surprise Pegasus personnel. Kendra Shaw is slightly shocked, but more due to the surprise that Cain is dependent on anyone. Jurgen Belzen and Jack Fisk do not seem to be at all fazed or uncomfortable with this relationship during the formal dinner after the Fall of the Scorpion Fleet Shipyards (Razor). Therefore, this is in keeping with writer Michael Taylor's comments that "the point about Cain’s and Gina’s relationship is that the fact that they had a same-sex relationship was no big deal".
Sam Adama casually mentions to his nephew Willie Adama that he used to try to flirt with men in a district the two are visiting (CAP: "Rebirth"). Sam's marriage to Larry, taken with his status as an enforcer for the Ha'la'tha, suggests homosexuality is not seen as in conflict with traditional masculine roles and attitudes.
Judging by comments made by producer/writer Jane Espenson and on Serge's Twitter account, homophobia does not exist and never has existed in the Twelve Colonies, and heterosexual and homosexual relationships are not thought of in different lights. Therefore, the word "gay" does not exist and homosexual marriage has been legal for as long as marriage has existed.
Bisexuality has not been seen until "Hero", with the culmination of a ménage à trois between Caprica Six, Number Three, and Gaius Baltar. It is uncertain how this is viewed in Colonial society, but since it is apparent that the Cylons model their behavior after their human creators, it is more than likely that sexual acts involving multiple partners is derived from Colonials.
Also, Gina Inviere can be considered bisexual due to her involvement with both Helena Cain and Gaius Baltar (at different times), though her relationship with Baltar is marred by the psychological effects of Inviere having been gang-raped on Pegasus.
In the webisode series The Face of the Enemy Felix Gaeta is revealed to be in a relationship with Louis Hoshi. Flashbacks to New Caprica also show him being involved with a Number Eight. Gaeta's sexuality had been teased early on behind the scenes, notably with the Season 3 gag reel where Alessandro Juliani attempts to hit on a marine protecting James Callis's Gaius Baltar, and later appears to be having a sexual dream about "Gaius".
In an interview, Ronald D. Moore stated that the bisexuality of Caprica Six and Inviere may or may not be typical of all the Six copies, or all the twelve Cylon models: "We sort of always talked about the Cylons being basically bisexual in all formats. They didn’t really have gender roles within the twelve models kind of thing, but we never really played that idea out so I don’t know if we ever really established that as part of the mythos, but that was something we sort of talked about. We pretty much established that some of the Sixes, there was the Six that was in a relationship with Admiral Cain so we know that that’s part of some of the Sixes, whether that means that applies to all the Six models, we just never got into that depth, that kind of detailed stories of them." 
Moore also said that "We’re in the process now of starting to think about what Caprica the series will be and what the storylines are and it is something that we’re talking about in our sort of nascent writers’ room where we have some people together and we’re just talking about what it could be and we are talking about it as an active thing, like okay, how can we work in gay, lesbian and bisexual storylines into this and that – it’s just not there yet, but it is part of the discussion."
Inter-racial and Inter-species
Although there are periodic mentions of prejudice between the quasi-castes of different colonies, no dialogue has indicated any taboo among Colonials regarding relationships between humans of different [real-world] ethnic or racial groups, nor even an acknowledgement of real-world ethnicity; each of the twelve colonies appears to be composed of a mixture of real-world human ethnicities.
In addition to the many inter-racial and inter-ethnic relationships not resulting in marriage (well, confirmed marriage), a full one half of the post-apocalypse marriages depicted are between spouses of different real-world races: African Anastasia Dualla and Caucasian Leland Adama, and East Asian Sharon Agathon (née Eight) and Caucasian Karl Agathon (cf Kara Thrace and Samuel Anders, and Callandra Tyrol (née Henderson) and Galen Tyrol [all four appear predominantly Caucasian]). Moreover, interbreeding between what would be real-world Caucasians and East Asians is presumably so commonplace that Dr. Cottle had a still-born Eurasian infant readily available, to secretly switch with Hera Agathon on President Roslin's order.
Humans and humanoid Cylons can and frequently do engage in consensual sexual intercourse. Relationships between humans and Cylons are viewed negatively by those who see Cylons as nonpersons, a viewpoint which becomes less and less common.
- Ellen Tigh and various men
- Simon O'Neill and Giana O'Neill
- Caprica-Six and Gaius Baltar
- Gina Inviere and Helena Cain
- Sharon Agathon and Karl Agathon
- Samuel Anders and Kara Thrace
- Gina Inviere and Gaius Baltar
- Galen Tyrol and Cally Tyrol
- A Number Eight copy and Felix Gaeta
- A Number Three copy and Gaius Baltar
- Tory Foster and Gaius Baltar
- Lida and Gaius Baltar
Cylon Simon and human Giana O'Neill were married before the apocalypse, with Giana unaware of her husband's Cylon nature but Simon well aware. Three of the four post-apocalypse marriages depicted are between humans and Cylons: Cylon Sharon Agathon and human Karl Agathon, human Kara Thrace and Cylon Samuel Anders, and human Callandra Tyrol (née Henderson) and Cylon Galen Tyrol. Of the three, the Agathons were the only marriage entered into while both (or either) spouse was consciously aware that one was a Cylon. The only post-apocalypse marriage shown between humans is that of Anastasia Dualla and Leland Adama. The only pre-apocalypse marriage depicted as surviving both the Cylons and Adm. Cain is that between Final Five Cylons Ellen Tigh and Saul Tigh.
Heterosexual fellatio among Colonials is implied by Laura Roslin's statement to Tory Foster, "I don't really care if you have to spend the night on your knees praying, or just on your knees. I want a name." (TRS: "Guess What's Coming to Dinner?")
- The religious controversy surrounding Rya Kibby's abortion suggest that the Colonial faith (or the Gemenese interpretation thereof) contains doctrine pertaining to sexuality, possibly in a similar fashion to many real world religions (TRS: "The Captain's Hand").
- The presence of child prostitution under Phelan's black market indicates the presence of pedophilia within Colonial society. The practice of child prostitution is viewed with loathing and disdain by Colonials such as Lee Adama, who ultimately kills Phelan after discovering this practice aboard Prometheus (TRS: "Black Market").
- Prostitution is legal in Colonial society, with consenting adult women such as Shevon offering their services to adult men such as Lee Adama (TRS: "Black Market"). This fact is a nod to the socialator practices touched upon in the Original Series. However, prostitution is not considered respectable, as Tom Zarek and Major Adama's conversation shows. Prostitution of young men for female clients has also been established (CAP: "Retribution").
- In addition, the Colonials have pornographic material like Nymph magazine (TRS: "Scar"), although it is uncertain whether or not pornography is viewed in the same controversial light as it is in America and some other cultures.
- The spines of some humanoid Cylons have been seen to emit a red glow during copulation. It is unclear whether or not this is visible to the human eye and could be used to detect Cylons. Nevertheless the real-world metaphorical use of the term "glowing" is used by Colonials to describe women sexually satisfied and/or in love.
- Marriage and engagement are practiced by the humans of the Twelve Colonies, and were practiced by the Cylons of the Thirteenth Tribe on Earth. In the Colonies, marriage vows are considered sacred oaths. Women generally take their husbands' surnames, but not always. Men do not change their name, except in the group marriage example noted below. There is no evidence of any similar practice to marriage among the modern Cylons, though two of them married humans.
- Marriages between more than two people have been shown to be legal on Caprica, though unusual. Upon learning that Clarice Willow is part of a group marriage, Lacy Rand is surprised but accepting and mentions knowing classmates who are children of group marriages. The Willow family surname comes from Desiree Willow (CAP: "Rebirth").
- Ryan, Maureen (16 November 2007). Answers to your 'Razor' questions and clues about 'Battlestar Galactica's' final season (backup available on Archive.org) (in ). Retrieved on 16 November 2007.
- The Tighs wear wedding rings in the flashback to the destruction of Earth at the end of "Sometimes a Great Notion"
- After Elton Interview With Jane Espenson
- Serge's Twitter
- Jensen, Michael (7 October 2008). Scoop on "Virtuality", the first U.S. science fiction series to include gay characters (backup available on Archive.org) (in ). Retrieved on 7 October 2008.
- Caprica-Six mounts Baltar thus in the Miniseries.
- Baltar is shown atop Kara Thrace in "Kobol's Last Gleaming, Part I", and Tory Foster in Faith, Lee Adama is shown climbing off of Thrace in "Unfinished Business", et al.
- Caprica Six is shown glowing atop Baltar in the Miniseries, Sharon Agathon is shown glowing atop Helo in "Six Degrees of Separation" and writer commentary for "The Face of the Enemy" confirms that "Sweet Eight" similarly glowed while having sex with Felix Gaeta on New Caprica.
- Laura Roslin referring to Tory Foster in "Guess What's Coming to Dinner?", Felix Gaeta referring to Anastasia Dualla in "Sometimes a Great Notion".