11.   And the reason men die younger than women may be found in the sexual behavior of worms.

12.   And though it is too early to tell if the program is changing sexual behavior among young South Africans, it is unquestionably reaching its intended audience.

13.   And the sexual behavior of men and women has long been measured, at least partly, against that tradition.

14.   As a consequence, Simon, a professor of sociology at the University of Houston, was an advocate for a much broader acceptance of differing sexual behaviors.

15.   As a result, sexual behavior is typically more diverse among adolescents than among adults.

16.   Attorneys for Jones want to use the Lewinsky case as evidence of a pattern of sexual behavior by Clinton.

17.   Bill Clinton is not the first president whose sexual behavior has become an issue.

18.   Biologists began to see female sexual behavior with new eyes.

19.   Bioethicists worry that if the vaccine shows only partial effectiveness, it could spark an increase in risky sexual behavior.

20.   -- Human sexual behavior is imperfect.