Hold down Ctrl + Shift +c , then type forcetwins in the cheat box. This can only be done when the sims is wearing maternity, and has a bump. Then when the sims gives birth, they should have two.
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How can I have boy girl twins on the sims 3 pets ps3
In the cheat box type: forcetwins.
To get twins, you can use the cheat "forcetwins" in the cheat console after your sim is pregnant.
No sorry there is no motive cheat on the sims pets. Edit: There is none for Sims Pets, but there is one for Sims 2 Pets. It is 'maxMotives', also type in 'help' in the Sims 2. That will give you a large list of cheats. Note: Must be in Sims 2, or it will not work.
On the Sims 2 if you want your sim to have twins,just type in the cheat boxforcetwinsand when your sim gives birth she will have twins!!|Warning: I think this cheat only works on macs