Scientists now know that many cases of male infertility have genetic origins.
Deletions on the Y chromosome are the most common known cause of little or no sperm production. One particular region of the Y chromosome, known as AZFc, appears to account for infertility in about 10 percent of those men who produce inadequate amounts of sperm. Since it was pioneered in the early 1990s, ICSI has become the preferred method for circumventing severe male infertility. The technique involves injecting single sperm into individual eggs and transferring the resulting embryos into the fallopian tube. ICSI is ideal for men with Y chromosome deletions because it requires only a few sperm, which usually can be retrieved from the patient's semen or testes.