Male factor problems as a contributing cause of infertility are very common. Male infertility is reported as a factor in 30-50% of infertility cases. In fact, many fertility specialists will recommend a semen analysis as one of the very first tests that should be done. It is relatively simple, inexpensive and yields much information. The two main causes of male factor infertility can be divided into either problems in manufacturing sperm or problems in getting sperm outside of the body (ejaculation of viable sperm). Sperm manufacturing problems can arise from problems in the testicle itself or from signaling problems from the brain to the testicle. Problems in ejaculation of sperm can arise from obstructions such as previous vasectomies to spinal cord injuries resulting in damage of nerves that innervate the testicle and male reproductive tract. The initial work up for sperm problems should include a comprehensive semen analysis which will evaluate the semen against fertility standards. These include the volume of the ejaculate (2-6mL), concentration of sperm (>20M/mL), motility (>50%) and morphology (Strict >14%). The semen analysis will frequently drive the remainder of the male evaluation if warranted. For example, in severe male factor cases, where concentration is extremely low, a hormonal and genetic evaluation of the male partner including an FSH, LH, total testosterone level, TSH and prolactin might be indicated. These tests will assist in determining if the problem lies in the proper signaling of the testicle from the brain in order to manufacture sperm. A further evaluation including a blood karyotype will further assist in determining if there is a genetic abnormality in the male causing lack of sperm manufacturing. Once these things are ruled out, then issues of obstruction must be considered. This will usually involve a urologist who specializes in male infertility. After a thorough history and physical exam of the male partner, a urologist might perform an ultrasound of the testicle, a dye test (vasogram) of the male reproductive tract, and possibly a biopsy of the testicle. There are all rather minor procedures that require very little down time. Treatment of male factor infertility can range from intrauterine inseminations to in vitro fertilization (IVF) with intracytoplasmic sperm injection (ICSI). In severe cases, it might be necessary to biopsy the testicle, a procedure called “testicular sperm extraction” (TESE). The biopsied sperm cells can then be used to inject into the eggs for hopeful fertilization. This procedure can diagnose as well as treat severe male factor cases. Some cases of male factor infertility are beyond using the male partner’s sperm, and in these cases, there is still hope by using donor sperm. The use of donor sperm is safe and effective.