Study Says Fathers’ Weight and Habits Can Shape a Child’s Future Health

For years, discussions about childhood obesity and a baby’s health before birth focused almost entirely on the mother. A new review says that view is incomplete: a father’s weight, diet, exercise, overall health and stress levels before conception may also affect a child’s later risk of obesity and metabolic problems.

The review, published in Current Obesity Reports, was led by Matthew J. Landry, a public health lecturer and clinical dietitian at the University of California, Irvine, together with John James Parker of Northwestern University. After examining research from the past decade, they concluded that sperm can carry more than DNA. In men with obesity, studies have found poorer semen quality, including lower sperm counts, weaker motility and more DNA damage. Large studies also found that children of fathers with obesity face a higher risk of obesity themselves, even after accounting for the mother’s weight.

The article highlights a 2024 Nature study suggesting that a father’s preconception diet can affect offspring health. In that work, data from families and experiments in mice showed that male mice fed a high-fat diet before conception had offspring with more metabolic disorders. The researchers pointed to small RNA molecules in sperm as a possible mechanism. The review also notes a more hopeful finding, sperm is not fixed forever. In men who lost substantial weight after bariatric surgery, a Cell Metabolism study found major changes in sperm patterns, including in genetic regions related to appetite control.

The critical window appears to be the three to six months before conception, when sperm used in fertilization are formed. Beyond biology, fathers also shape children’s habits after birth through food choices, cooking, screen time, physical activity and daily routines. The review says greater paternal involvement is linked to healthier eating patterns and lower obesity risk in children. Landry said fathers have been “historically neglected,” and argued that men should be included early in pre-pregnancy care, alongside nutritional counseling, exercise support, mental health care and preparation for parenthood.