In The Sims 2, the 'Move In' proposition is available regardless of the genders of the Sims involved. There are also hacked objects which allow a Sim to be moved into a household. Unlike marriage, it can be accepted if the two Sims are good friends. Whether it will be accepted depends on the relationship between the two Sims, the quality of the asking Sim's house, and the mood of the Sim being asked. In The Sims, the 'Move In' proposition is only available if both adult Sims are of the same gender.
