There are many plausible reasons why women would approach a man with a baby that have nothing to do with how babies smell.

For example, some women just like looking at babies. They may be reminded of their own babies, or thinking of babies that they'd like to have someday. Also, women may be more likely to talk to a man who seems non-threatening (men with babies are probably responsible for very little violent crime!).

While it is possible that babies smell a certain way, and even a whiff of that scent makes women more aggressive, I'd be surprised if this were the most relevant pathway for 'why women are more likely to approach a man with a baby than a man without a baby'. The main variable is the presence of the baby, not how the baby smells.

Now if you tell me that women were more likely to approach you when you had recently been holding a baby...then I think we can draw up articles of incorporation and start a new cologne company.

There's a lot of weird psychology in how humans work. Many men also notice that they are more interesting to other women, only after they enter a relationship with a woman. Apparently it's one of natures way of conserving energi. One woman have already spend the time to assess the man, and judged him to be a good partner, so it might be easier to just go after this pre-vetted man.

I would guess they decided to approach you before they smelled the baby. How close do you have to be to smell a baby. If they were close enough to smell I suspect the had already approached you by the strictest definition of approach.

Isn't that the opposite of what this article is saying (unless the woman were really aggressive in their cooing)

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.

I don't think it's the smell. My puppy works for this too.