How overweight men could be affecting their unborn babies’ weight – and affect the DNA of their children

Overweight men are more likely to father underweight babies, a new study has shown.

Researchers from the University of Sao Paulo’s Ribeirao Preto Medical School found that obesity can impact the structure and quality of men’s sperm – and affect the DNA of their children.

Examining the weight of 89 parents and their newborns, they discovered that the larger a man’s waistline and BMI, the smaller their baby’s head circumference.

‘There is a great deal of research regarding the link between foetal development and maternal health, but the fact is that the father’s health also has a significant impact on the development of the baby both during pregnancy and after birth,’ said researcher Dr Mariana Rinaldi Carvalho.

‘Our study was the first involving Brazilian families to show that the higher the father’s BMI, the lower the baby’s birth weight, evidencing the father’s importance to the baby’s health and development.’ 

Research has shown babies born at a particularly low weight have a higher risk of developing type 2 diabetes, cancer and heart disease later in life.

Researchers from the University of Sao Paulo’s Ribeirao Preto Medical School found that obesity can impact the structure and quality of men’s sperm. File image

The study suggests that poor diet, a sedentary lifestyle or smoking could cause changes to the genes passed from father to child.

Babies born to overweight fathers suffer growth restrictions while still in the womb which cause them to fail to reach the size and weight they ought to be.

‘We now know that environmental stressors such as overweight can influence the structure and quality of the father’s sperm, altering gene expression and affecting the DNA of his children,’ said Dr Carvalho. 

‘Our findings show that just as maternal nutritional counselling is key, so is the need for a preconception change in paternal habits.’