A recent
review of the scientific literature has controversially suggested that breastfeeding does not bestow the benefits that have been claimed for it in recent times.
..it is very hard to separate the benefits of the mother’s milk from the benefits of the kind of mother who chooses to breastfeed.....In other words, breastfeeding studies could simply be showing what it’s like to grow up in a family that makes an effort to be healthy and responsible, as opposed to anything positive in breast milk.
I'm not qualified to question that view and the logic does seem valid, but by chance I recently heard
Sarah Blaffer Hrdy mention (in an aside about infant abandonment) that primates who breastfeed experience increased prolactin and oxytocin levels which helps them bond with their offspring.
The marketing lessons: replication isn't enough and the most significant impact of your product/service isn't always the obvious one.