"The most marked difference between the sexes documented in this study lies in the reasons for their choice of majors. Women were about twice as likely as men to have chosen an S.M.E. major through the active influence of someone significant to them. […] By contrast, men were almost twice as likely as women to cite ‘being good at mathematics and/or science in high school’ as a reason for choosing an S.M.E. major. Whether they were actually better prepared or skilled than women entrants is not the issue. What matters is that many young men than young women felt confident in their readiness to undertake higher level science and mathematics."

Elaine Seymour and Nancy M. Hewitt. Talking About Leaving: Why Undergraduates Leave The Sciences (1997), p. 77.