Pregnancies will now last a single day. Once the baby is born they will mature for a further one day (Regardless of what age you pick).
A stupidly simple mod... but still... Tadaaaa.
This is good for experimenting with trait inheritance. But very OP for general use, use sparingly!
If you just want the 'growup' times shortened to one day, us this instead. It leaves pregnancy length alone and doesn't spoil the challenge of the game (It's what I use).
Use one or the other, not both. It shouldn't do any harm, it's just that there's no point.