--Apollodorus, Bibliothekes II.iv.9, translated into Latin by Thomas Gale (1675)
The Amazons excelled in waging war, and trained in all of the "manly" arts. And if they conceived a child from their dalliances with men, they only raised their female offspring. They would remove their right breast so that it wouldn't interfere with their spear throwing ability, but left their left breast alone, so they could still be able to nurse their children.
SUGGESTED READING: This is an account of the mythical race of Amazons. For a detailed and factual analysis of the people who inspired this myth, I encourage you to read Adrienne Mayor's The Amazons: Lives and Legends of Warrior Women Across the Ancient World. This book is targeted for an adult audience, so younger readers might find this book difficult to read.