I truly truly wonder if its because guys in general are more prone to find these kinds of pursuits and not because they are necessarily expressions of virility or male ego, but just the chemistry of the male mind.
Several people have suggested that in more or less those words. Let me try to dispose of it once and for all.
There is very likely some truth to this statement; however, it is untestable. More to the point, it is not a very helpful way of looking at the isssue. Let me expand.
Although there are surely some inherent differences in male and female minds -- or, more precisely, different tendencies or averages -- it's impossible in practice to tell which differences are inherent and which are cultural. It's fair to say that people tend to underestimate the importance of culture; history is littered with differences between different groups that were once assumed to be innate and later proved to be cultural.
Am I wrong or are most sports and hobbies male dominated even if its 60%? Even skiing and scuba is primarily male.
Sports are a case in point. There have always been sports that were exclusively female (field hockey) or dominated by women at the highest levels (softball). But fifty years ago it would have been obvious that sports are inherently male-dominated.
Now it's not obvious at all. Soccer, the fastest growing sport in the U.S., and one of the few sports that's played the same by both sexes, is definitely more popular among girls than boys in my region of the U.S. Given the current trends, I wouldn't be at all surprised to see women dominating in many sports within the next 50 years.
I pointed out a similar example in my first response. Fifty years ago, boys did far better than girls in math and science. Now the reverse is true; girls outperform boys in these subjects at the high-school level, and in some areas of science women outnumber men among PhDs.
It's worth noting that everyone in this thread who has suggested that the difference in astronomy particpation is innate has been a man. This is totally unsurprising.
Throughout history, when one subgroup has been in a position of greater power than others, the dominant subgroup has always believed that the difference is due to inherent superiority -- whether because they're chosen by God, racially purer, bigger, braver, smarter ... whatever.
The subordinate subgroups are generally less enthusiastic about that point of view.
But leaving questions of truth aside, it's simply not helpful to say that the difference is innate. That's no more or less helpful than saying that the difference is cultural. Both of those statements are surely true (they are in no way contradictory!), but they're just a way of avoiding asking the hard questions.
If there's something innate in male biology -- or something cultural -- that makes men more prone to stargazing than women, what is it? That's the interesting question.