Gender
In all Sims games, there are male and female sims, but only minor differences other than appearance. The most prominent is that one male sim and one female sim is required to create a baby, as well as gender pronouns when describing the sim in a pop-up. Female sims usually get more customization features in CAS. In the Sims 2, there are two doors with one exclusively for both sexes. Also, with the new pregnancy feature, females get pregnant through woohoo and males can get pregnant through alien abduction. In the Sims 3, certain relationship labels are organized by gender.