I would find this argument much more convincing if it were supported by people who actually have children. My mother goes beserk over a smiling infant in a way I cannot begin to comprehend (I am usually afraid I will accidentally hurt them). My husband, likewise, has an instant affinity for babies and always tries to communicate and play with them. He was raised Jewish with the idea that it is unclean to have animals in the home and does not find animals particularly adorable. In our culture we are inundated with anthropomorphised images of animals in television and given stuffed toys and pets that we take care of like children. It's not that surprising that we find animals cute when we focus so much attention on them as if they were little people. I do not know that such evaluations of 'cuteness' would hold cross-culturally, especially in cultures where people do kill and eat 'cute' animals on a regular basis.