Reproductive Technology

There are many causes of infertility. Abnormal semen causes the infertility problems of about 30 percent of couples seeking treatment. Tubal disease and endometriosis in the female partner account for another 30 percent. A female partner's failure to ovulate accounts for 15 percent, and the inability of sperm to penetrate the woman's cervical mucus accounts for another 10 percent. The final 15 percent of couples seeking treatment are infertile for reasons that cannot be diagnosed.

Many couples can be helped to overcome infertility through hormonal or surgical interventions. Women experiencing ovulation disorders may benefit from treatment with oral drugs such as clomiphene citrate, or through the injection of gonadotropins, such as follicle-stimulating hormone, which has about a 75 percent success rate. Women with tubal disease can be helped by various types of reconstructive surgery, but the success rate is only about 33 percent.

However, many infertile couples cannot be helped by such standard methods of treatment. Instead, as a last resort, couples that want children must turn to newer techniques that bypass one or more steps in the usual physiological processes of ovulation, fertilization, and implantation. Commonly This eight-cell human embryo is an example of a blastocyst. referred to as "assisted reproductive technology," these techniques include in vitro fertilization (IVF), gamete intrafallopian transfer, zygote intrafallopian transfer, donor insemination, egg donation, embryo cryopreservation, intracytoplasmic sperm injection, tubal embryo stage transfer, and intrauterine insemination.