IVF or 'in vitro fertilisation', means fertilisation outside the body. It is a method which has helped many women to have babies, and first came to public notice in 1978 with the birth of the first so-called test-tube baby, Louise Brown. Since then 76 clinics have been set up in the UK to offer IVF treatment. All are licensed and monitored by the Human Fertilisation and Embryology Authority (HFEA), which is a public body set up by an Act of Parliament.

Briefly, IVF involves the collection of eggs and sperm which are mixed outside the woman's body in a culture dish or test tube. Any resulting embryos are left to grow for about a day to check that they are developing normally and then up to three embryos are transferred into the woman's womb. If the treatment is successful, one or more embryos will implant in the lining of the womb and for each a foetus and placenta will develop. The woman will then be pregnant, just as if the woman had conceived normally.