Fashion , Modesty , Clothing , and Hijab by country. While births outside marriage are common and fully accepted in some parts of the world, in other places they are highly stigmatized, with unmarried mothers facing ostracism, including violence from family members, and in extreme cases even honor killings. Governments can be complicit in violence against women, for instance through practices such as stoning as punishment for adultery. In the s, many female academics, including scientists, avoided having children. Girls' bodies undergo gradual changes during puberty, analogous to but distinct from those experienced by boys. The breast evolved from the sweat gland to produce milk, a nutritious secretion that is the most distinctive characteristic of mammals, along with live birth.