Kids born to unhealthy parents are already pre-programmed for greater risk of poor health, with higher odds of developing metabolic diseases such as diabetes and cardiovascular disease, scientists say.
Researchers at the University of Adelaide say environmental factors prior to conception have more influence on the child's future than previously thought.
"This really is a new frontier for reproductive and developmental research," said Professor Sarah Robertson, corresponding author and Director of the University's Robinson Research Institute.
The research concludes that parental influences on a child begin before conception, because stored environmental factors in the egg and sperm are contributing more than just genetic material to the child.
"Many things we do in the lead up to conceiving is having an impact on the future development of the child - from the age of the parents, to poor diet, obesity, smoking and many other factors, all of which influence environmental signals transmitted into the embryo," Robertson said.
"People used to think that it didn't matter, because a child represented a new beginning, with a fresh start. The reality is, we can now say with great certainty that the child doesn't quite start from scratch - they already carry over a legacy of factors from their parents' experiences that can shape development in the foetus and after birth. Depending on the situation, we can give our children a burden before they've even started life," said Robertson.
This includes a higher risk of metabolic diseases, such as diabetes and cardiovascular disease. The likelihood of conditions like anxiety and immune dysfunction can also be affected.
Robertson says current research is also showing that the fathers have a much greater role to play in this than previously thought.
"A few lifestyle changes by potential parents and improvements in the right direction, especially in the months leading up to conception, could have a lasting, positive benefit for the future of their child," Robertson said.