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, though they do have a larger range of differences in The Sims 3. However, differences in female and male Sims' reactions are minor to nonexistent, and gender stereotypes do not seem to have had much influence on the way EA formatted the two genders. However, it does appear to have had some influence. For example, in Sunset Valley, which is featured in The Sims 3, there are many more over-emotional female Sims than male ones, and many more handy male Sims than female ones. Still, reactions of female and male Sims to the same situations appears to be equal, if they have the same personality.

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 careers 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.

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.

In The Sims Medieval most gender differences are similar to the ones present in The Sims 3, but there is a new element not present in any other games in the series. When babies are born, they will be friends with their mother but will have a more distant relationship with their father, whom they will be acquaintances. Unlike the real middle ages, men and women are free to pursue any profession.

Gender differences in toys
There are clear gender differences in toys; some are stereotypically thought of as being for girls, and others as being for boys. Of course, the player can choose whether to have Sims follow these stereotypes. Also, when Sim toddlers and children make free will choices about which toys to play with, they disregard these stereotypes. Given free choice, girls will not necessarily pick up "girlish" toys, nor will boys necessarily pick up "boyish" toys.