Almost all causes of male infertility are usually related to sperm disorders – either too few in number or of inadequate quality. It’s for this reason that one of the first investigations of the infertile couple is a semen analysis laboratory test. The male, unlike the female, is constantly renewing his supply of germ cells, and a single ejaculate of semen may contain as many as 200 million individual sperm cells. A sperm count of 20 million per millilitre semen is considered normal for fertilisation. The sample should also show that more than half the sperm cells are motile, and around one-third of normal shape.