par·i·ty 2 (pr-t)
1. The condition of having given birth.
2. The number of children borne by one woman.
This form is from the Latin parere, to give birth, or bring bring forth. Not what I think about when we're talking about a word that also means equality. I mean, I have 2 kids, and I can tell you from experiences with my friends with more kids, having 2 is by no means equal with having 4, (although I at times wonder if one of my kids is equal to several on his own, but that's another story altogether). No, that's not exactly what they meant. Something more like..."Consider the parity of the moms when getting a mom's group together so you know how many kids to expect" would probably be more like it. So, after all of that, parity is not always equal.