Here's a well written column by Michael Gurian on accepting natural differences between men and women.
Liberals have spent a lot of time arguing that differences between men and women are created by socialisation alone: by upbringing, education, media influence and so on. They have preferred to believe this because they don't want an unchosen quality like our manhood or womanhood to significantly influence who we are. This is because it's a liberal first principle that we should be self-created by our own individual will and reason - that this, in fact, is what defines us as human.
Hence the liberal attempt to overthrow the influence of inherited sex roles, which is still going on today.
Modern science, though, is undermining the liberal position, as the Gurian piece makes clear. The conservative attitude, that there are natural differences between men and women which will be reflected in the nature of social life, and particularly family life, is being increasingly vindicated.