I posted this on a genetics thread. Crossposting here because some readers will find it interesting... and perhaps informative about personal anatomy.

About 1/4 of us have an extra pair of nipples which show up as a small bump under each arm. It is unusual, but sometimes they are capable of lactating. As mammals, we have a "milk line" down each side of our chest. It begins high up under the arms, shifts slightly toward the center of the chest where normal breasts develop, then continues down nearly to our waist. Occasionally this shows up as a row of nipples which may go down to the waist. A tribe in South America carried a trait for having 4 fully developed breasts. If you visit Cajamarca, one of the churches has carved decorations including one of a woman with 4 breasts. If you scroll down about 2/3 of the way on this weblog, you can see a picture of the "four-breasted" woman on the church.

https://web.archive.org/web/20150127211550/http://irbtomato.blogspot.com/

I've seen photos of one person who grew a fully developed breast on the back of her leg. If you look online, you can find a few pictures of anomalous nipples including one person who had an extra pair of breasts under her arms. I've read of a few people who had rows of nipples down their chest including one who had 8 nipples in 2 rows of 4. People tend to be very self-conscious and insecure about body features they were born with. Empathy, understanding, and acceptance are universal themes we should all practice.