When a woman undergoes weight loss surgery, her own body isn't the only one affected: children born to women after they've undergone gastric bypass procedures exhibit key genetic differences compared to siblings born prior to the surgeries.

That's according to a small new study published in PNAS this week. Researchers tracked 20 women, all of whom lost nearly 100 pounds following a specific type of gastric bypass surgery — wherein one's digestive system is redirected to limit food intake and caloric absorption — as well as their children. When the team evaluated children born after a mother's surgery, they found 5,698 genes that were expressed differently from those of siblings born before a mother had lost weight.

"It appears that there's an effect that is transmitted to the next generation."

Many of the affected genes are thought to be implicated in heart health, metabolism and inflammation. Indeed, these same kids — who were, on average, 15 years old — tended to have healthier blood pressure, weight, and fasting insulin levels than their peers in the study. "It appears that there's an effect that is transmitted to the next generation," the study's co-author, Marie-Claude Vohl, told HealthDay. "This may have some consequence later in life for the health of the children."

The findings contribute to a growing body of research into epigenetic inheritance — a phenomenon whereby parents appear to pass altered genetic traits to their offspring, without any changes to underlying DNA structure. Researchers are still unsure how this process might work, given that it diverges from the widely accepted notion that genes are "reset" between generations. In other words, that a parent passes on DNA — but not the myriad changes in genetic expression they've acquired throughout their own lives.

Plenty of questions unanswered

Compelling as it is, this latest research leaves plenty of questions unanswered. For one, it didn't evaluate whether weight loss itself, as opposed to weight loss surgery, is behind the phenomenon. Nor do investigators know whether a father's weight loss might have a similar impact. It's also possible that epigenetic inheritance wasn't at play — instead, kids born following their mother's weight loss surgery might have been raised in a healthier home environment, one that included better nutrition and more exercise, than their older siblings.