Men are at an increased risk of developing testicular cancer if their testes failed to descend at birth, a new study has found.

Cryptochidism refers to cases where the testes do not descend into the scrotum, but instead stay within the abdomen. This is the most common birth defect found in boys, affecting some 6%.

Scottish scientists analysed over 700 relevant medical papers, which featured a number of studies involving over two million boys. They found that those who had cryptochidism were almost three times as likely to go on to develop testicular cancer later in life.

The scientists emphasised that testicular cancer is currently the most commonly diagnosed cancer in young men, aged 20-45, with rates increasing significantly worldwide in recent decades.

They called for more research in this area to determine whether surgical correction of cryptochidism reduces this increased risk of cancer and to determine whether the degree of descent plays a role.

"The most poignant question this study raises, however, is whether the risk of malignant transformation is sufficiently significant to warrant regular follow-up," they said.

Details of these findings are published in the journal, Archives of Disease in Childhood.