The study has no external funding; all costs are covered by ESHRE. There are no competing interests.

The 13th ESHRE report on ART shows a continuing expansion of the number of treatment cycles in Europe, with more than half a million of cycles reported in 2009. The use of ICSI has reached a plateau. Pregnancy and delivery rates after IVF and ICSI remained relatively stable compared with 2008 and 2007. The number of multiple embryo transfers (3+ embryos) and the multiple delivery rate have shown a clear decline.

In comparison with previous years, there was an increase in the reported number of ART cycles in Europe. For the first time in 5 years, the pregnancy rates failed to show a year-on-year increase. Compared with 2007, the number of transfers of multiple embryos (3+) and a multiple delivery rate showed a marginal decline.

Nonobstructive azoospermia (NOA) represents the most severe expression of male infertility, involving around 1% of the male population and 10% of infertile men. This condition is characterised by the inability of the testis to produce sperm cells, and it is considered to have an important genetic component. During the last two decades, different genetic anomalies, including microdeletions of the Y chromosome, karyotype defects, and missense mutations in genes involved in the reproductive function, have been described as the primary cause of NOA in many infertile men. However, these alterations only explain around 25% of azoospermic cases, with the remaining patients showing an idiopathic origin. Recent studies clearly suggest that the so-called idiopathic NOA has a complex aetiology with a polygenic inheritance, which may alter the spermatogenic process. Although we are far from a complete understanding of the molecular mechanisms underlying NOA, the use of the new technologies for genetic analysis has enabled a considerable increase in knowledge during the last years. In this review, we will provide a comprehensive and updated overview of the genetic basis of NOA, with a special focus on the possible application of the recent insights in clinical practice.