I sympathize (as you know from previous chats) and have been there many times. Just the other day I was chatting with my book club friends about this exact issue, and how when people bring babies into an office setting, literally every woman in the office rushes over to stare at the baby. Whatever this gene is that other women have, I'm missing it.
I just went to a housewarming last night where there were no babies, but several kids about 7 yrs. old. When I arrived, all the kids and parents were sitting around a table and very little adult conversation was possible because the kids were yelling their heads off (or talking in that way 7 yr. old boys do, very loud and interrupting everyone). When I was a kid we would have never gotten away with talking that loud and obnoxiously, interrupting adults, etc. I could see them through the kitchen window as I walked up to the house, and it took all my nerve to still ring the doorbell! I sat there for about an hour while we watched the kids eat (is there anything more disgusting than watching kids eat?...as if I want to eat any chips or crackers that have been mauled by kids) and when they finally went outside, and later upstairs to play, it was still boring, and interrupted every few minutes by someone's kid thumping down the stairs to whine about something.
These people's lives revolve around their kids so much that it's hard to find anything else to talk about. Example subjects: Sally just had the flu, and so did her husband, but they were lucky the kids didn't get it. Work topics came up, but were dwelled upon because generally these people only work because they have to (ie. why talk about work if you don't like it?)
However, I was somewhat glad I made the effort because my friend hosting the party (who has one son) didn't have many of her friends turn up, and it was mostly her husband's friends at the party. She thanked me several times for coming (again when I saw her today) and I know she feels bad that their events always turn into kid-oriented things. Her son is 7 now and I think she's looking forward to more independence as he gets older.
Although generally I would agree with other poster (why bother, save yourself the grief) in this case I think my two hours of annoyance made a big difference to my friend. I share your pain!