If I had to generalize (always an unsafe thing to do), I would say that modern writers have tended to allow more options for women and restrict them less to traditional roles. The mere fact that so many important modern writers have been women has helped promote this kind of development, and the mere fact that the modern age has permitted the rise of so many women writers says a good deal about changes in attitudes toward women in the modern period.
My reading is largely non-literary -- that is, I read for enjoyment rather than enlightenment and so I read science-fiction, fantasy, thriller, etc., instead of books that have a "message." However, I do notice a trend in modern books to have the main female character as more of a prop instead of a main part of the action. For example, a police thriller will have a male and female cop, but the male cop will be proactive while the female cop will be inactive -- Male Cop is a beat officer but gets the action, Female Cop is a Forensic Pathologist and spends all her time at a table, weighing organs. I'm not saying that there are no strong female characters in fiction, but they tend to be window dressing instead of the window itself.
This largely depends on what modern writer you are talking about. There are modern male writers who continue to regard women as sex objects, for example, Philip Roth, and there are modern male writers who regard women as as full partners in life, for example, Udall, in The Lonely Polygamist. As for female writers, I don't think there is any particular distinction between the modern era and any other era, since we have never had any difficulty regarding ourselves as complete people.