Donor egg is an option for couples whose eggs no longer fertilize and produce healthy embryos. Egg quality generally declines with advancing female age but it can occur at any age. Ovarian reserve is a measure of "egg quality" and is evaluated during the infertility workup. Other candidates for donor egg include women who may have been born with absent ovaries (rare) or those whose ovaries were damaged by cancer chemotherapy or radiation. Donor eggs may also be used in cases of unexplained infertility and severe endometriosis or ovaries destroyed due to ovarian disease like endometriosis/ tuberculosis.