Infertility is defined as the failure to conceive after one year of having regular unprotected intercourse. For couples who have already managed to conceive in the past infertility is definied as failure to conceive after 6 months of having regular unprotected intercourse. The World Health Organisation estimates that 1 in 6 couples are affected by subfertility; some believe this number to be higher.

Infertility can result from male, female, or combined factors and in approximately 15% of the cases infertility remains unexplained. Male causes of infertility include sexual disfunction, sperm abnormalities, azoospermia (no sperm in the ejaculate) or the presence of anti-sperm antibodies. Female infertility factors include lack of ovulation due to PCOS or other causes, endometriosis, tubal blockage and polycystic ovaries. Genetic disorders and chromosome abnormalities can also result in infertility. A woman's age is the most significant factor affecting the chances of success.

In the past 30 years, over 3 million babies have been born thanks to Assisted Reproductive Technology (ART). In Europe, ART is responsible for over 2% of births every year.