History Main / HereditaryHomosexuality

** In ''The Revival'', Jack's grandson is sent to "conversion therapy" when his ultra-religious mother fears that he's gay, partly due to her anxiety over this trope. The kid's certainly got campy interests and mannerisms, but is really too young to say with certainty yet.

* Sibling protagonists Kassandra and Alexander from ''VideoGame/AssassinsCreedOdyssey'' are both bisexual, as are all of their potential love interests. ({{Justified}} by the EveryoneIsBi setting of Ancient Greece.)

* Sibling protagonists Kassandra and Alexander from ''VideoGameAssassinsCreedOdyssey'' are both bisexual, as are all of their potential love interests. ({{Justified}} by the EveryoneIsBi setting of Ancient Greece.)

** In ''The Revival'', Jack's grandson is sent to "conversion therapy" when his ultra-religious mother fears that he's gay, partly due to her anxiety over this trope. The kid's certainly got campy interests and mannerisms, but is really too young to tell yet.

** In the revival, Jack's grandson is sent to "conversion therapy" when his ultra-religious mother fears that he's gay, partly due to her anxiety over this trope. The kid's certainly got campy interests and mannerisms, but is really too young to tell yet.

* Taken UpToEleven with Fearghal from ''Series/ComeFlyWithMe''. He's one of eleven brothers who are all air stewards; they're also all gay (except one, who's bi).

If fiction, of course, it's up to the writer. Fairly often, you may see gay characters who have relatives who are also gay. In particular if a gay character has kids with TheBeard or via HomosexualReproduction those kids are more likely to be gay than not.

[[AC: Live Action Film]]

* In ''Literature/{{Cyteen}}'' Jordan is heavily implied (and outright stated in the sequel) to have a gay relationship with his male [[ArtificialHuman azi]] assistant Paul, his son Justin has a similar relationship with an azi named Grant. Of course Justin is also a clone of his dad.

* In the ''Literature/HeraldsOfValdemar'' series, Vanyel the last Herald-Mage, a notorious historical figure, was gay. He however had four children via being a ChosenConceptionPartner. One of the gay men of the main time period is descended from Vanyel's first child.

[[AC: Live Action Television]]

* ''Series/DegrassiTheNextGeneration'': Paige's older brother, Dylan, is gay. Paige herself later enters a long-term relationship with a woman, although its not really clear if this is a case of BiTheWay or IfItsYouItsOkay.

** Rick and his father are both gay, and came out on the same day even.

* ''Roleplay/AcademyOfMerlin'': There are three siblings, two boys and one girl, who are all gay.

* A number of studies estimate that [[http://link.springer.com/article/10.1007%2Fs10508-008-9386-1 around 30%]] of the variance in sexual orientation is explained by genetic factors. This does ''not'' mean that there's a 'gay gene', but rather that a large number of genetic variants may marginally increase or decrease one's propensity towards homosexuality. Notably, while this degree of heritability is significant, it's much lower than the heritability of physical traits like height and weight, or of mental traits like intelligence, openness and extraversion.
* Various studies have put forward the role of [[https://en.wikipedia.org/wiki/Pleiotropy pleitropy]], the ability of a gene to present in multiple ways depending on various factors, as a contributor to determining a person's sexual orientation. It has been noticed that the female relatives of gay men often have an easier than average time getting pregnant and staying pregnant, suggesting that the gene or genes that cause homosexuality when it presents in men also increases fertility when it presents in women, explaining both how it would be passed down and why it would be preserved by evolution.

* In ''Webcomic/{{Homestuck}}'', Dirk Strider is gay, as is his ectobiological daughter Rose. [[spoiler:His ectobiological son Dave also turns out to be bisexual, meaning that everyone directly related to Dirk is non-straight in some way.]]

* One old joke has a client going to a doctor about his attraction to men, and how his father, his brothers, his uncles, and his cousins also have that. When the doctor asks if there is anyone in his family who are not attracted to men, the client replied that his sister does.

* In ''Another Gay Movie'' Andy is gay and his father is either gay or bisexual (and his mom is a drag queen although the character is apparently female). Played for squick when the two nearly hook up in a public men's room. The sequel gets squickier when the two had anonymous sex, finding out the truth only after.

* Michael on ''Series/GueerAsFolkUS'' learns that his father is a drag queen.

* ComicBook/AmericaChavez is a lesbian, much like [[HomosexualReproduction her mothers]]. It's implied that

In Real Life, the causes of [[UsefulNotes/{{Homosexual}} homosexuality]] are unclear. Though one hypothesis, as counterintuitive as it may seem, posits the existence of a "gay gene" that increases the chance of someone being homosexual.

* That ''Webcomic/CyanideAndHappiness'' strip where a kid comes out to his parents, who both follow suit and break up.

In Real Life, the causes of homosexuality are unclear. Though one hypothesis, as counterintuitive as it may seem, posits the existence of a "gay gene" that increases the chance of someone being homosexual.

* A number of studies estimate that [[http://link.springer.com/article/10.1007%2Fs10508-008-9386-1 around 30%]] of the variance in sexual orientation is explained by genetic factors. This does ''not'' mean that there's a 'gay gene', but rather that a large number of genetic variants may marginally increase or decrease one's propensity towards homosexuality. Notably, while this degree of heritability is significant, it's much lower than the heritability of physical traits like height and weight, or of mental traits like intelligence, openness and extraversion.