receiver I think that the point is employees make (often large) profits from their employees, and that they have a set of duties and responsibilities with regard to those employees. Employees are human beings, and human beings have children. You can't expect otherwise.
Even in small businesses I think the issue is not black and white. My stepmother runs a beauty therapy shop in a small town. She has three members of staff, all of them women in their 20s. One of them has been with her since she started the business five years ago and is excellent - intelligent, kind, reliable, trustworthy, popular with the customers - and has helped my stepmother build the business to a profitable position. She works the longest hours of anybody in the business and if she left lots of her clients would go with her or go elsewhere. Now she's getting married and my stepmother is moaning that she might have to cover her while she's on maternity leave, if she has a family. I think this is short-sighted in the extreme - you employ human beings, not robots, and human beings have children. And in return for all the profit and work they give you you have certain duties and responsibilities towards them - paying them above minimum wage is one, and accepting that they might have children is another. It's better for the business anyway that they keep this young woman working there in the long term than lose her altogether.
Basically I think it comes down to the question - do we want to live in a world where there are fewer female doctors (even when we really need to see them), fewer women making our laws in parliament, or prosecuting/defending both men and women as lawyers and policewomen, fewer investigative journalists or scientists or product designers who are women? We've been there before and there's no doubt that understanding of crimes like domestic violence and rape, or scientific research into pregnancy and childbirth, for instance, have been transformed by the fact that we now have a more equal workplace. I don't think we want to go backwards on that, and I don't think we want to bring our daughters up thinking that if they have children their chances in the workplace are seriously compromised. So I think it's right that employers play a part in it.