By Kate Kelland LONDON (Reuters) – Men who start smoking before the age of 11 risk having sons who are overweight, British researchers have found, adding to evidence that lifestyle factors even in childhood can affect the health of future offspring. “This discovery of transgenerational effects has big implications for research into the current rise in obesity and the evaluation of preventative measures,” said Marcus Pembrey, a professor of genetics at University College London, who led the study and presented its findings at a briefing on Wednesday. While previous studies in animals and in people have found some transgenerational health impacts, the evidence so far is limited. It points, however, to epigenetics – a process where lifestyle and environmental factors can turn certain genes on or off – having an effect on the health of descendants.