The group’s 2014 report on more than 14,000 individuals showed that sons of fathers who had started smoking regularly before puberty (<13 years) had increased fat mass during childhood, adolescence, and early adulthood…mdedge.com, Legacy from young boys’ smoking: More body fat in granddaughters, great granddaughters, Marilynn Larkin, Feb 2022
“If our study is correct, it is the exposure (to cigarettes smoking) before the gonads have fully developed that is key to the physical development of subsequent generations,” she noted. “We assume that such exposures will leave some sort of epigenetic mark on the sperm that will subsequently develop.”
Further, when fathers of maternal grandfathers started smoking pre-puberty, their great-granddaughters, but not great-grandsons, had excess body fat at ages 17 (+ 5.35 kg) and 24 (+ 6.10 kg).