There are many options to preserve fertility, but they have to be considered quickly before undergoing cancer treatment.

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Cancer has the potential to impact the fertility of men and women in direct and indirect ways. The types of cancers of the reproductive system that threaten a man's fertility range from testicular to penile cancer, while ovarian and uterine cancers are examples of reproductive system diseases that can make it difficult -- and in some cases, impossible -- for a woman to conceive.

When the endocrine system is targeted by cancer, a man or woman may become infertile. Even if the reproductive and hormone-producing centers of the body remain untouched, cancer can still impact the ability to have children. This is because stresses of any kind -- those associated with lung cancer, for example -- can signal the body to concentrate all its energies on fighting the disease rather than producing sperm or eggs [sources: FertilityProRegistry; Dawson].

In many cases, it's not the cancer itself that threatens fertility. It's the treatment required to eliminate the disease or slow its progress that's responsible for causing a temporary or permanent inability to reproduce. For many years, cancer patients weren't even told that chemotherapy, radiation or surgery would have an impact on their chances of having children. The physician's focus was solely on combating the immediate problem rather than considering the future effects of the life-saving efforts.

But advances have been made in the way doctors are advised to handle the issue. Since 2006, the American Society of Clinical Oncology has encouraged doctors to speak with patients about the threats to infertility posed by various cancer treatments and the options the patient has to preserve fertility, even if the prospect of having a child is years in the future [source: National Cancer Institute].