Gender

In all The Sims games, there are male and female Sims, but except for their appearance and clothes (females generally have a larger choice of clothes) the differences between them are minor, excluding The Sims 3 where male and female Sims have a large range of differences. However differences in female and male Sims' reactions are minor to unexistent and gender stereotypes don't seem to have much influence in the way EA formatted the two genders, though in Sunset Valley, featured in The Sims 3 for example there are many more over-emotional female Sims than males ones and many more male handy Sims than female handy Sims, which hints to the fact that EA own's gender judgement takes a very influent role to make female and male Sims different, besides this, reactions of female and male Sims to the same threads appears to be equal, but female Sims may exhibit more enthusiasm, joy, fright and sadness by speaking, they show more their emotions, as the real tendency, and because creators tend to make male and female Sims, with, on average, different personalities, they may seem very different, but if the personality given for both male and female Sims is the same, there appears to be no difference in the way they react, at all. The most prominent difference is that one male Sim and one female Sim are required to create a baby through in-game interactions. Also, gender-specific pronouns will often be used when describing the Sim in a pop-up or on a tag, such as those which can appear for some jobs and moods.

As in real life, male and female Sims can clearly be distinguished by their appearance. Basically, females will have breasts and will look more feminine, with larger hips, smaller shoulders and waist, and will have lower muscle tone. Males will lack breasts and look more masculine, with larger shoulders and smaller hips, and will have higher muscle tone. They will also have different sets of voices. Female Sims will typically have higher voices, and male Sims will typically have lower voices. These features are purely cosmetic and have no effect in the game. On another note, children and prior life stages have none of these physical differences, although most of their customization features are separate between genders.

In The Sims 2 and The Sims 3, there are some customization features in Create a Sim that are only available to one gender. For example, only male Sims will have options for facial hair, and a larger scale at fitness also increases a female Sim's breasts size, but thicker waist and legs.

While using the toilet, a male Sim will stand up in front of it if his bladder is still high enough. When a female Sim takes a shower, the game, if unmodded, will censor her breasts.

In The Sims: House Party, The Sims: Hot Date, The Sims 2, and The Sims 3: World Adventures there are doors that are used exclusively by one sex, usually used for washrooms on community lots.

With the new pregnancy feature in The Sims 2, females can get pregnant through woohoo and males can get pregnant through alien abduction.

In The Sims 3, certain relationship labels are organized by gender.

Gender Differences in toys
There are clear gender differences in toys, some of them stereotypically indicated to girls, and other indicated to boys. Although, it is choice of the player whether the player will follow these stereotypes, and if observing a female toddler in The Sims 3 and see which toy she is going to play with, if there's a large range of toys present; teddy bears, dolls, cars, it may be seen that she will not necessarily pick the "girlish" toys, the same happens to boys.