We have friends (a husband and wife) who have a now 4 year old boy. We like these friends a lot and we like their kid (sometimes). FI invited them over to watch the "Doctor Who" Christmas special next month, but when he told me he invited them, I said, "Is there a nice way to ask them to come sans bebe?"
Now, I'm sure you all know how I feel about kids. But hear me out.
Our apartment is very cluttered. We have 10 pounds of crap in a 5 pound bag. Our living room is dominated by a very large couch, a glass coffee table and a very old, large wall unit with heavy glass doors. The rabbit occupies most of the dining room (and is skittish). The kitchen is still full of boxes with stuff my mom gave me before she moved. Don't even get me started on the state of the bedroom.
We simply have no room for a kid - a 4 year old - to come to our apartment and feel comfortable. We don't really have running around space or kid-friendly toys or books or games. Nothing that would keep a 4 year old occupied for the 90 minutes it would take for the grownups to watch "Doctor Who" in peace.
FI managed to get the wife on the phone today and explained in a nice, subtle way that our apartment was not very kid friendly at this point in time. She said, "I understand". But for some reason I feel bad about having to come right out and let it known that we can't have her, her husband and her kid here. They often do not get invited places because they make a habit of bringing their kid when their kid has not been invited. Also, the last time one of FI's friends came over, she brought her two rambunctious young sons (ages 2 and 4) without asking and it traumatized me. I feel like now when kids are a possibility, I have to make it clear we want to keep it childfree.
Were we rude about it? Is it fair to ask friends to not bring their kids to our apartment?
Has anyone else had to go through a similar situation where they had to ask someone to not bring their children somewhere? How did you handle it? Did it change your friendship?

170 Invited (holy crap!)
98 are coming to party!
29 have other plans
43 need to respond!
"Bside - You're just too sexy for your own good" ~ leia1979
"True love = I still love you even though we hang out all the time and most other people would be tired of each other already" ~ flygirlmeg