Historic Attitudes
Attitudes are hard to measure and harder to change. However it doesn't takes a genius to know that women are knowledgeable about these issues and men aren't. There was a time in America when men were more in touch, but in the 50's and 60's men were excluded from birth. Eventually this created a whole generation of men who were without experience and knowledge about pregnancy and childbirth. Men were taken from the proper place as medicine shrouded birth from men's view and domain. Following generations weren't told anything about birth. Men had become knowledgeless. They became accustomed to being out of the picture. They also did not teach their sons anything as they had nothing to tell them.
Then as birth became a medical event, and society bought into that idea, women began fighting back, wanting control of their births and pregnancies. Some of these women began challenging the status quo. They lead a movement back toward natural childbirth. Midwives, often treated as criminals, began working toward licensing. Birth centers were founded to offer consumers alternatives to a traditional hospital birth. Women became politically activated and fought the system. Some of them brought their men, those willing to lend a hand and provide them with moral support.