How do The Sims get pregnant on The Sims game

You may have both Gender Sims in a bed, and relax them on the bed, click on one of the sims, and it will say try for a baby. After they are done and asleep tere might be a soft tune. If there is that means she is pregnet. Her stomach will get bigger and bigger and in a couple of days she will have her baby. WARNING: She will be a little bit more hungry and tired.