When it comes to the health of your children, what do you worry most about? If lack of exercise tops your list, you're not alone.

A new survey finds not getting enough exercise was ranked a "big problem" by 39 percent of adults surveyed. That was followed closely by childhood obesity (38 percent) and smoking and tobacco use (34 percent), drug abuse (33 percent) and bullying (29 percent).

"I think there are a few factors that come into play here," said Deborah Carr, Sociology Professor at Rutgers University.

"First, Michelle Obama does have this 'Let's Move' campaign which gives the issue very high visibility. So, most people have either heard of it or at least they feel they should comment on it. The other is that it really is among the most common problems. For young people today, about 20 percent are obese and about one-third are overweight, a direct result of inactivity. Because it's so common, any one of us could have an overweight child, so most parents will worry about it."

Rounding out the bottom half of the top ten concerns were stress (27 percent), alcohol abuse (23 percent), teen pregnancy (23 percent), internet safety (22 percent), and child abuse and neglect (20 percent).

"Some of these other more serious problems, like drug abuse and teen pregnancy are much more rare from a statistical standpoint and there's also a bigger stigma attached to them. So, many parents might say 'oh, my child would never become pregnant, my child wouldn't do drugs,' so they don't really allow themselves to worry about the very dire prospects, but they can realistically consider the possibility that their child might become overweight or obese," said Carr.

"Many of us tend to worry about things we can control and we can control our child's diet, we can get them to exercise and make activities available to them. The other problems that are much more dire are more difficult to handle. If our child falls in with a bad crowd, or gets pregnant or does drugs, those problems are much more difficult to overcome," said Carr. "Also, keep in mind, the percentage gaps between top concerns wasn't that big so, I think most parents worry about these problems fairly equally. It's just the lack of exercise and obesity are more common so more people worry about it."