There’s a theory about the specific suckling technique the breast engenders, which develops the muscles needed for speech. Williams becomes convinced – and has convinced me – that breasts evolved as a driver of female and infant survival, and men’s obsession with them arrived not “in lockstep”, but some time later. “Perhaps, all along, the breasts were calling the shots,” she concludes.
…
The composition of the breast makes …[breastmilk]… a magnet for environmental toxins, so they “carry the burden of the mistakes we have made in our stewardship of the planet”.

This is from a book review on guardian. Interesting but not something that will be in my read stack anytime soon.