Well, there is also a possible psychological component. Lots of women end up seeing single men as a possible threat. With a baby in your arms, you can signaling

Well, there is also a possible psychological component. Lots of women end up seeing single men as a possible threat. With a baby in your arms, you can signaling that you are much safer to them in a multitude of ways, many of them in a way that both parties are not necessarily aware in a conscious level, but we do have sub conscious processes that alter our thoughts and behaviors. But the smell is also a factor, that's the thing, humans are the single hardest animals to study, cause we are way, way too complex.