Employees who are infertile may qualify for reasonable accommodations under the ADA. That's true even if the underlying medical condition that caused the infertility has been cured. As a result, you may be required to give infertile employees time off for fertility treatments and even adoption planning.
Recent case: A computer programmer developed cancer of the uterus and had to undergo a hysterectomy. When she sued for disability discrimination, the question arose whether she was truly disabled simply due to her infertility. The court said "Yes." Because childbearing is a major life function (as the Supreme Court decided years ago in the Bragdon v. Abbott case involving an HIV-positive person), infertile employees are disabled and entitled to accommodations to deal with infertility. (Yindee v. CCH, Inc., No. 05-3069, 7th Cir., 2006)