Sorry, there are no cheats to choose gender. Some people swear that there are certain ways to get a gender, but they don't work for everyone. (One way people say is to have select Try for baby with the guy if you want a boy, and with the woman if you want a girl, but it's not actually a proven thing.)
There are hacks that you can download that let you choose genders, but if you're not into downloading hacks, there's only one other way. It's kind of annoying, but it will work eventually...
When your mom starts having her baby/ going into labor save your game. Then when she has her baby, if it's not the gender you want, EXIT THE LOT WITHOUT SAVING then go back in and do it again, until you get the gender of baby you want, then SAVE.
Hope I helped!
