Having a fat DAD can up your chances of developing female breast cancer
Previously most research focused on how a mum's weight affect their babies' risk of cancer
DADS who are obese are more likely to put their daughters at greater risk of breast cancer, a new study warned.
Daughters of podgy fathers but slim mums, like Family Guy's Peter Griffin, are overweight when born and throughout childhood.
They also have delayed development of their breast tissue as well as increased rates of breast cancer.
The study by Georgetown University Medical Centre, in Washington DC, is the first to examine the effect of a dad being obese on his offspring's future cancer risk.
It suggested carrying extra pounds changes the DNA of a man's sperm which has health consequences to their yet unborn daughter.
Assistant professor Dr Sonia de Assis said: "This study provides evidence that, in animals, a fathers' body weight at the time of conception affects both their daughters' body weight both at birth and in childhood as well as their risk of breast cancer later in life.
"Of course our study was done in mice, but it recapitulates recent findings in humans which show that obese men have significant epigenetic alterations in their sperm compared to lean men.
"Our animal study suggests that those epigenetic alterations in sperm may have consequences for next generation cancer risk."
Researchers found evidence that obesity changes a gene in both the dad's sperm and the daughter's breast tissue, which is linked to alterations in body weight and cancer development.
The assistant professor added: "Until we know about this association in men, we should stick to what we all know is good advice.
"Women - and men - should eat a balanced diet, keep a healthy body weight and lifestyle not only for their own benefit but also to give their offspring's the best chances of being healthy."