A new study links a father's age at the birth of his child to the risk that the child would develop cancers of the blood and immune system as an adult, especially for single kids.
However, the study did not find any association between having an older mother and these cancers.
According to lead author Lauren Teras from American Cancer Society, the lifetime risk of these cancers was fairly low-about one in 20 men, but the study highlights the need for more research to confirm these findings and to clarify the biologic underpinning for this association.
In the research, data from men and women enrolled in the American Cancer Society Prevention Study-II Nutrition Cohort was analysed. It was found that among 138,003 participants there were 2,532 cases of haematologic cancers indentified between 1992 and 2009. The researchers uncovered a strong, positive association with paternal age among participants without siblings.
In the group participants whose fathers were aged 35 years or older at the time of their birth the risks of haematologic malignancies was found to be 63 per cent higher as against those whose fathers were younger than 25.
The study points out that further research was needed to better understand the association between paternal age at birth and hematologic malignancies.
The study has been published in the American Journal of Epidemiology.
The new study comes at a time when an increasing number of men and women had been delaying having children until at least 35-years-old, and the age of men and women deciding to have children for the first time continued to climb.
This new study was one of a few studies that had shown the increased risk to the child when the parents were older, and more studies were still emerging on the long-term impacts of older parents.
The study showed that there were higher risks of childhood and adult-onset cancers when the parents were older.
According to experts, the ''hygiene hypothesis'' might have been at play here, considering that there was an association between those that did not have siblings.
The hygiene hypothesis was the idea that exposure to a mild infection during childhood, which happens more frequently with the more siblings, was important for the overall development of the immune system.
According to the hygiene hypothesis there was a reduction of immune-related diseases with the more siblings present in the household.