Women in the advancement of science?

Found something surprising in Charles Murray's book Human Accomplishment from 2003. One would suspect that more women have contributed to top scientific discoveries during the latter half of the 19th century when women really have made an entrance in society in many fields but nothing much have happened. If anything the contribution has been lower.

During 1901-1950 the percentage of women with Nobel Prizes in Chemistry was 4%, Medicine 2%, Physics 2% and Literature 11%. During 1950-2000 the percentages were Chemistry 1%, Medicine 4%, Physics 1% and Literature 8%. The total has thus gone down from 4% to 3%.

The only way I can explain this phenomenon is that the people contributing with Nobel Prizes belong to the group of extremely intelligent individuals that are more common among men than women. Average intelligence is the same for men and women but men feature more extreme talent and also more low talent. It could also mean that all extremely talented indivduals are found and activated.

If you accept the notion that the contribution is lower, it could be that emancipated women are less interested in science.