Sex

For the social construct sometimes confusingly referred to as "sex", see gender.

Sex - WITHOUT GOING INTO TOO MUCH DETAIL - is the means by which species reproduce, and a display of affection common among adult romantic pairs in many species. Many people, both real and in MS Paint Adventures, have specific sexual preferences commonly known as their sexuality.

In Problem Sleuth

Problem Sleuth establishes that “any man secretly wishes to have sex with a female version of himself” (see Female Alter Ego) - however certain male characters seem to show a vested interest in the male sex, seemingly discrediting this notion.

In Homestuck

Sex is a theme that runs deep through Homestuck, in both absence and presence. Notably, the process of ectobiology means that a majority of Homestuck's main characters were not born from sexual reproduction; and in contrast, the game of Sburb that dominates the comic's plot can be considered a form of reproduction for the frogs that are the Homestuck world's universes.

Among humans

Although Aranea Serket describes human reproduction as “exclusively heterosexual”, human sexuality varies widely. Dirk Strider in particular is exclusively attracted to other men; however he considers the term “gay” to be “antediluvian”, likely due to his version of Earth's exposure to Alternian reproductive norms (see #Among trolls). Dirk's offspring Dave Strider and Rose Lalonde also show interest in the same sex, maintaining relationships with Karkat Vantas and Kanaya Maryam respectively.

The Condesce “found our usual method of procreation revolting”, and after taking control of Earth attempted to install a system more similar to her own species', involving regular contributions of genetic material used to create babies long after the original donors had died.

Among trolls

Troll breeding pairs are “8isexual”, and it appears to be because of this that terms like “homosexual” are not “A THING” in the Alternian vocabulary. In order to reproduce, a troll must produce "genetic material" from both the flushed and pitch quadrants, which are considered the "concupiscient" or reproductive quadrants. Again, WITHOUT GOING INTO TOO MUCH DETAIL, because trolls have “a complicated reproductive cycle”:

“The genetic material [...] is a combinative genetic mix from the matesprit and kismesis pairs, respectively. The pails are all offered to the mother grub, who can only receive such precombined material. She then combines all of it into one incestuous slurry, and begins her brooding.

This doesn't mean the initial combination was for naught, however. In the slurry, more dominant genes rise to the fore, while the more recessive find less representation in the brood. Especially strong matesprit and kismesis pairings yield more dominant genetic material. The more powerful the complement or potent the rivalry, the more dominant the genes.”

At least in troll folklore, the genetic descendants of trolls tend to share their sign, and are fated to experience similar events.

The mother grub herself seems to reproduce asexually, with an egg-like organ called the matriorb found inside virgin specimens being used to “Hatch A New Mother Grub”.

Sexualised imagery of anthropomorphised animals, for whatever reason, feature heavily in Alternia's upper class culture.

Among cherubs

See also: Cherub#Cherub Sex

Cherub reproductive pairs could be loosely described as heterosexual, being between a "male" cherub and a "female" cherub; however they are complicated by also being between "good" and "evil" cherubs. These pairs are based on mutual antagonism rather than affection, much like the troll pitch quadrant, and notably sex between two cherubs culminates in both individuals taking the form of immense snakes, “each an astronomical unit in length”, and doing deadly battle for dominance. The dominant partner impregnates their mate - with every cherub seemingly having both motile ("male") and non-motile ("female") sex cells, making them more like some hermaphroditic organisms on Earth such as slugs and snails - and the result of this battle determines the sexual makeup of the offspring.

Among other races

Though Aranea's monologue on the topic is cut short by a disinterested Vriska Serket, context clues might indicate that leprechaun reproduction is homosexual, though how exactly this could work is unclear.

In addition to extensive knowledge on the above topics, Aranea also indicates that she has some knowledge about “ogre sex” and “salamander shipping”, indicating these species may have their own methods of reproduction despite their apparent immaculate generation in each game of Sburb. In contrast, though they are known to form various kinds of romantic relationships, carapacians seem to have no visible genitalia, likely owing to their use of ectobiology labs in the Veil to procreate.