Ever heard of epigenetics? If not, don’t worry–most people haven’t. Broadly speaking, the field of epigenetics maintains that something that happens to you during your lifespan might be passed on to your offspring–and, more importantly, to your grandkids.

Researchers now suspect that a  baby born to a woman who smoked while pregnant could pass on lung damage–along with an increased risk of developing asthma–to her own children. In other words, the smoking grandma could be hurting her grandchild long before that grandchild’s mother is even born, long before that future grandchild is a gleam in anyone’s eye.

That raises an interesting idea. There’s something of an epidemic of childhood asthma these days–despite the fact that air pollution levels are down from what they were a generation ago. Could it be that at least some of this asthma is the result of grandmothers who smoked when they were pregnant with their own daughters? Interesting idea.

Now, it’s important to understand that most of these epigenetic studies have been done on rats. But scientists believe that rats’ and human’s physiology are close enough that what affects one has a pretty good chance of affecting the other.