---------------------------

.... AAS members born between January 1, 1980 and January 1, 1985, 56.8 percent are women. In the next older cohort of astronomers, his study shows that of members born between January 1, 1975 and January 1, 1980, just 39.7 percent are women.

---------------------------

The article suggests that the AAS aggressively recruits among freshman university students, but about 1/3rd of the female students do not graduate from university, and terminate their memberships in the AAS. Also an AAS membership might not be very useful to its members, who inevitably look elsewhere.