There are a number of medical treatments (including chemotherapy) and other cancer treatments that can destroy the ability to procreate. Read about ovarian cryopreservation - a hope for the future
Fertility Preservation
Interst in freezing and storing gametes (sperm and eggs) for later use is nothing new. By the 1960’s the technology to freeze sperm was reliable enough. So what about freezing eggs?
Hormones and Endocrine Disrupting Chemicals:
Low--Dose Effects and Nonmonotonic Dose Responses
This FAQ by Pete Myers
Regarding the human egg: How old is too old? Perhaps we are asking the wrong question. Remember the psychological argument about nature vs. nurture? Let’s rephrase the topic altogether. How can we help women in their mature reproductive years produce healthy children? I propose that the answer is found in the nature vs. nurture discussion. Nurturing the follicle in the 120 days before ovulation will produce a healthy egg, free of transmutation, free of the need for medical intervention.
A new way of thinking about fertility and in particular infertility.