I know a female who's taken meth, coke, opium, acid, and other drugs. how will that affect her kids if she has kids one day? she's in treatment now.

None: If she remains off the drugs. If not, then certainly there will be effects, including withdrawal after birth.

Parenting & Presence: The most important thing is that if you take drugs, you can't be present to the needs of your kids when you're stoned. If she gets into recovery she will have a good chance to be a more present parent and a role model for future children. Hope this answer helps.