I've never been made to feel I have "less social validity" when not in a relationship, nor have I ever felt pressured to be in a relationship or have kids. That said, I've spent no significant time without being in a relationship since I was maybe 25 or so, if that makes a difference. Still, I don't think anybody treats me differently based on whether I'm in a relationship or not -- and I've never been asked when I'm getting married or having kids. I'd have no patience with people asking me questions that are none of their damn business.
That kind of thing is stupid anyway and why in the hell would I care if people or society thought less of me or treated me a certain way because I wasn't in a relationship? Women shouldn't give a shit about stuff like that -- do what you want and what makes you happy, and the hell with what anybody else thinks, expects, or wants.
And James, I'm sure you're kidding about the grandkids thing, but ew. If my parents want joy in their twilight years, they can move to the mountains and hang out with their grandpuppy.