wastes money proving the painfully obvious. >> but as we hear from abc's senior medical contributor dr. timothy johnson there's more there than meets the eye. take a listen. >> reporter: viva la difference, say the french. and when it comes to the great divide between men and women, a best-selling book put it another way -- "men are from mars and women are from venus." now a study published in the online journal public library of science one says the two sexes could almost be from different planets. researchers used a new method to compare multiple trait personality profiles of 10,000 men and women instead of just focusing on one trait at a time. the authors say they found striking gender differences. women scored significantly higher for sensitivity, warmth, and apprehension, while men rated higher in emotional stability, dominance, and rule consciousness. the study says sex differences in personality have been greatly underestimated, leaving each of us something of a stranger to the opposite sex. i'm dr. timothy johnson. >> not a big stutter. we'll debate this after the commercial. we'll be right back.