Boys born as a result of IVF could inherit their father's infertility, scientists have warned.

A study has found that boys conceived using the popular form of fertility treatment often had shorter fingers  -  a trait associated with infertility. It means techniques used to combat problems conceiving could be storing up problems for the future. However, the boys in the study are too young for it to be known whether they are infertile.

Almost one in 50 babies born in Britain is conceived artificially. Nearly half of these use a treatment called ICSI  -  intracytoplasmic sperm injection  -  in which an individual sperm is injected directly into the female egg. It means it bypasses the normal 'survival of the fittest' competition which sees only the healthiest sperm make its way to the egg, break through and fertilise it.

Men with low sperm counts often have ring fingers the same length as their index finger  -  while fertile men are more likely to have a ring finger that is longer. Finger length is set within the first 14 weeks of pregnancy and is linked to testosterone exposure which is, in turn, governed by a specific set of genes.