No Mods Required!
The June 2016 update for The Sims 4 added more gender options for Sims. One of those options is if the Sim will be able to be pregnant or be able to impregnate other Sims. With this option same-sex couples will be able to become pregnant and have children with no adoption or mods required! If you already have a same-sex couple in your game and you want them to have kids, follow these easy steps demonstrated by the Larson family and the Matson Family:
Firstly, go to a dresser and select “Change Sim”
When CAS has loaded go to the custom gender settings.
If you have a gay couple, choose the “Become Pregnant” option for one of the Sims. Make sure their partner has the “Get others pregnant” option selected
If you have a lesbian couple, choose the “Get others pregnant” option for one of your Sims. Make sure their partner has the “Become Pregnant” option selected.
And that’s it! Your couple should now have the “Try for Baby” interaction!