(anonymous post) 

 :Actually, no.  First, the etymology is for the generic word "dozen"  not the phenomenon being discussed.  Second, disfigured, old and problem (rebellious, insolent, prone to escape) slaves often were sold in lots; they were not considered as valuable as, say, a woman of childbearing age or a strong, young male or female who had not been disfigured or crippled.  Third, again, every credible source places the origin of the dozens in the African American community.  Fourth, I'm a woman.  Fifth, I've heard far better.  I'm partial to:  "Yo' momma so fat, when she haul ass, she gotta take 2 trips."