Boys with a condition called cryptorchidism - a condition characterized by undescended testicles - are three times more likely to develop testicular cancer.

The condition is fairly common in boys who were born prematurely. It also occurs in 3 - 4% of full-term boys, according to PubMed Health. An undescended testicle is more likely to develop into a cancer.

For most boys who are born with either one or both testicles undescended, the problem gets corrected naturally in few months. Others might require a surgery that brings the testicle into the scrotum.

Testicular cancer affects men aged between 15 and 35. The risk is greater for boys who have undescended testicles and surgery doesn't lower the risk of testicular cancer in these men.

In the resent study, researchers analyzed data from studies conducted on the link cryptorchidism and testicular cancer risk. There were 9 case control studies, with 2,281 cases of testicular cancer, which had been diagnosed between the ages of 15 and 75 between 1965 and 2006. The studies had a total of 4,811 controls.

Researchers also looked at data of three cohort studies that involved 2 million boys whose health was tracked for a period equivalent to a period of 58 million person years. In these studies, 345 boys with cryptorchidism developed testicular cancer later in life.

Based on the two sets of data, researchers calculated that the risk of developing testicular cancer was almost three times higher for boys with cryptorchidism than for boys whose testicles descended normally.

Dr. Michael Ost from University of Pittsburgh Medical Center says that parents of these boys must know about the cancer risk and be vigilant to spot the early signs.

"I tell them that the risk of cancer in males between the ages of 18 and 35 is one to three in 100,000 and this puts them at an increased risk. So they have to be diligent in terms of watching their children and examining them on a regular basis - and when they come of age, teaching them to examine themselves," said Dr. Michael Ost, an associate professor of pediatric urology at the University of Pittsburgh Medical Center, reported NBC News.

Researchers say that the study leaves many more questions unanswered like how the degree of descent and surgical intervention affect risk of cancer.

"The most poignant question this study raises, however, is whether the risk of malignant transformation is sufficiently significant to warrant regular follow-up, as is the case with other premalignant states," the study authors added.

The study is published in the journal Archives of Disease in Childhood.