Originally posted by Maresche
The only threat to your sister from Mina is called Toxoplasmosis. It is a disease that is carried through cat feces and is only a danger to your sister if she is exposed to it while pregnant. If she has already been exposed (by having cats herself), then she is in no danger.

As long as she doesn't play in the litter box and washes her hands after playing with Mina, she'll be fine.
That's absolutely right. Look at all the Pet Talk babies in kimlovescats, Cataholic's and Sirrah' family

It can checked whether your sister is already immune against toxoplasmosis.