Gender preference

Gender preference is a feature of a Sim's personality introduced in The Sims 2, and carried forward into The Sims 3 and The Sims 4. It governs which gender a Sim, acting autonomously, may choose to interact romantically with.

Gender preference is a hidden aspect of Simology that can normally not be seen without the use of cheats, mods, or programs such as SimPE. In The Sims 3, gender preference can be set with the use of mods such as NRAAS Master Controller. Likewise, in The Sims 4, a Sim's preference can be set with a mod such as MC Command Center.

Scale
In The Sims 2, gender preference operates on a scale of -1000 to 1000, which SimPE represents as -10.0 to 10.0, rounded to the nearest tenth. In The Sims 3, it uses a signed, 32-bit integer. In The Sims 4, gender preference is on an integer scale from 0 to 100.

Changing gender preference
Each Sim who is a teen or older can develop a gender preference that is defined by the averaged total of all their romantic interactions with other Sims. For instance, if the majority of a Sim's romantic interactions have been with females, that Sim will have a preference for females, and vice versa, if the majority of the Sim's romantic interactions have been with males. Gender preference is fluid; a Sim's gender preference scores gradually change as they engage in romantic interactions with other Sims. Enough interactions can change a Sim's preference for a gender from negative to positive, or vice versa; e.g., a female Sim with a preference towards females who repeatedly has romantic interactions with male Sims may develop a preference for males. It is possible to influence the gender preference of townies and uncontrolled Sims by performing minor flirt interactions such as checking them out or whistling at them.

Newly created Sims, whether freshly out of CAS, or newly created townies, have a neutral gender preference, unless they are created as spouses, where their preference will be set to their spouse's gender. Even though most townies and NPCs start with a neutral gender preference, they may still autonomously show attraction to Sims of the opposite gender, but the chances are lower than for Sims who have a preference for that gender.

In general, the size of a Sim's preference for (or against) a gender affects how stable that preference is, rather than how strong it is. For example, a Sim with a -10/20 male/female preference isn't more attracted to females than one with a -1/2 preference. However, the first Sim's preferences will not be significantly affected if a male flirts with them once or twice, while the second Sim's will be.

The Sims 2
In The Sims 2, most pre-made Sims have a neutral or nearly neutral gender preference; they either have no preference for either gender, or no preference for one and a slight preference for the other. In rare cases, a pre-made Sim may have a slight preference against one gender, but no preference toward the other. Sims who are born in-game or are adopted start their teen stage with a neutral gender preference.

In general, romantic interactions will increase a Sim's gender preference for one gender by 2 and decrease that Sim's preference for the other by 1. However, there are some special cases. The "Do You Like What You See?" interaction affects gender preference, even though it is an "Ask..." action and not a flirt interaction. However, the "Scope Room" self-interaction introduced in The Sims 2: Nightlife does not affect Sims' gender preferences. Players with The Sims 2: University should note that autonomous flirting by an evil cow mascot will affect the gender preference of the Sim being flirted with.

A few pre-made Sims in The Sims 2 have pre-set positive preferences for both genders. It is not normally possible for a Sim to develop a negative preference for both genders, though it can happen with Sims who have a pre-set negative preference for one gender

The Sims 3
The Sims 3 operates with a similar system to The Sims 2, where gender preference increases by 2 for one gender and decreases by 1 for the other.

The Sims 4
In The Sims 4, successful romantic interactions increase a Sim's preference for one gender by 10, and decrease their preference for the other by 5. This makes the scale much easier to traverse than in The Sims 2 and The Sims 3, as only ten successful interactions are needed to max it out for a particular gender.

The Sims 2
In The Sims 2: Nightlife and later expansion and stuff packs for The Sims 2, Sims only show attraction and chemistry for Sims of their preferred gender, and only Sims of the preferred gender will be considered when a Sim uses the "Scope Room" self-interaction—though the gender preferences of the Sims being scoped will not be considered. This means that Sims with a neutral preference cannot use "Scope Room", but can be scoped. If a Sim has the same positive preference for both genders, the gender of the last Sim they interacted with romantically will be used.

The Sims 3
A player-controlled Sim can be commanded to perform romantic interactions regardless of gender preference, though it appears to be more difficult for romantic interactions in The Sims 3 to succeed if the Sim being pursued has a gender preference not associated with the pursuing Sim.

In The Sims 3: Generations, when a Sim throws a bachelor/bachelorette party, the gender of the entertainers will be based on the gender preference of the host. In The Sims 3: Seasons, Sims who try online dating will receive messages from Sims of their preferred gender, and the default selection of profiles that appears is also based on that.

The Sims 4
In The Sims 4: Romantic Garden Stuff, the "overwhelmingly positive" outcome for wishing for romance at a wishing well will summon a Sim of the wisher's preferred gender.