Gender Biased applicants

In the time I have worked on the rotifers, I have had the following assistants:

Lauren
Myfanwy
Rose
Laurel
Chris
Phoebe
Polina
Christina
Nicole
Deanna
Willard
Vincent
Catherine

That makes 3 males and 10 females. Hardly 50/50.

I was wondering why this was, if I was in some way unconsciously discriminating against male applicants, or practicing affirmative action. So I counted how many male and female applicants I have had in the last two rounds of hiring. The most recent I had 2 male and 8 female applicants. The previous time, I had 3 male and 13 female applicants. So if anything, I'm over-hiring males as compared to their representation in the applicant pool.

What I am wondering about now is why so many more females than males apply. The biology classes in my department have a slight majority of females, but not nearly that big. My guess is that because the project specifically investigates the evolutionary basis of menopause, and women tend to be more interested in (and comfortable with the topic of) menopause, fewer males are interested.