I don't think use of steroids produces permanant impact to a woman's ability to have children. The important thing is to make sure that all of the steroid is out of her system before trying to have kids. Basically look at leaving at least 6 months after her last cycle to start looking at having kids. Here's a little blurb on the topic:
From Anabolics 2000, page 13, Section on Steriod Side Defects -
Birth Defects:
Anabolic/androgenic steroids can have a very pronounced impact on the development of an unborn fetus. Adrenal Genital Syndrome in particular is a very disturbing occurrence, in which a female fetus can develop male-like reproductive organs. Women who are, or plan to become pregnant soon, should never consider the use of anabolic steroids. it would also be the best advice to stay away from these drugs completely for a number of months prior to attempting the conception of a child, so as to ensure the mother has a normal hormonal chemistry. Although anabolic/androgenic steroids can reduce sperm count and male fertility, they are not linked to birth defects when taken by someone fathering a child.
So if you're a chick who wants to be a mom soon, don't juice. Guys, juice away....