Simple answer: as far as chest equipment goes, men and women are exactly the same.
Yes, men could make milk.
The reason women have big breasts is because female hormones cause their breasts to grow, the hormones released during pregnancy cause them to lactate. If men are exposed to those same hormones the exact same thing happens, men do have estrogen and other female hormones in their bodies naturally (small amounts, released mostly by the adrenal gland) but testosterone suppresses their effects and causes hair growth, muscular growth, cartilaginous growth around the larynx and the differences in bone structure.
Frankly speaking the difference between growing up looking and sounding male or female depends entirely on the hormones.