Microdeletions on the long arm of the Y chromosome and their association with male-factor infertility

The treatment of male infertility has been revolutionised by the development of intracytoplasmic sperm injection (ICSI). In this procedure, only oocyte quality and individual sperm viability have been shown to affect fertilisation rates.1 In conventional in vitro fertilisation (IVF), approximately 50 000 morphologically normal, motile sperm are used for each oocyte to achieve acceptable fertilisation rates. In contrast, ICSI requires just one viable sperm per oocyte to achieve acceptable fertilisation rates. Palermo et al2 have demonstrated that ICSI is an effective method to overcome fertilisation failure in routine IVF. With the development of ICSI, there has been a rapid increase in the number and types of male infertility cases that are now treatable, to the point where only complete testicular failure is not.3 However, the rapid development of disorders being treated with ICSI has not been equalled by a rapid increase in our understanding of these disorders, in particular their aetiology and potential for inheritance.4