Male infertility is the primary cause or a contributing factor for about 40 percent of infertile couples. Intrauterine insemination (IUI) can be helpful if a man has mild to moderately low sperm counts or motility (the ability of the sperm to swim effectively). If IUI doesn't work or a man has more severe problems, intracytoplasmic sperm injection (ICSI) can be helpful. ICSI involves injecting a single sperm into a mature egg in the embryology lab. ICSI is also used if there is a concern about a genetic disease or if eggs have been previously preserved using the vitrification process.