Some did, yes. It was quite common for a slaveowner to have children by a slave woman. Mary Chesnut, a wealthy southern woman, wrote in her diary that every Southern lady "tells you who is the father of all the mulatto children in everybody's household, but those in her own she seems to think drop from the clouds, or pretends so to think." White women were haunted by the fear of their husbands, fathers or sons having sex with their slaves. "Slavery degrades the white man more than the ***** and oh exerts a most deleterious effect upon our children" wrote Gertrude Thomas of Georgia, who suspected that both her father and husband had black mistresses. Some men seemed to become very attached to the slaves they slept with. Catherine Hammond left her husband in 1850 because he refused to give up his slave mistress. Thomas Foster, a married planter in Mississippi, had an affair with Susy, one of his slaves. When his wife tried to sell her off the estate, he abandoned his family and took Suzy away. The slave women of course had little choice, they could hardly refuse a master who wanted them. Harriet Jacobs, who was sexually harassed by her master, called puberty "a sad epoch in the life of a slave girl" At the end of the Civil War somewhere between 10 and 20 percent of the slaves were believed to be part white.
America's Women by Gail Collins