31.   But no study has yet determined how early is early enough.

32.   But several leading experts on birth defects said the study had serious methodological problems.

33.   But long-term follow-up studies have yet to be done.

34.   But since studies have yet to document any hazards, even scientists are taking the plunge.

35.   But such studies have a fundamental drawback.

36.   But such studies have an inherent weakness.

37.   But the study also had drawbacks.

38.   But the study has little relevance to the current understanding of how to control weight, said Stunkard, who specializes in the treatment of obesity and eating disorders.

39.   But the new study has its skeptics, too.

40.   But the study has limitations, she also cautioned.