I must say I did not find it "calculating" - I thought I might, but was in fact moved by the plight of these women who had so much love to give but had just missed the boat for one reason or another. I thought back to the joy we had from our little ones (and still have from them as adults) and really wanted them to have the same. Our motives for having children are complex, but in the final analysis, however they are conceived, they are satisfying a basic natural imperative that we cannot explain.
I did have a niggling thought about the hurdles that prospective adopters quite rightly have to jump before becoming parents and wondered whether there ought top be some sort of vetting, but there is none behind the bike sheds so maybe that is unfair.