Telegony, Part 2 : Anomalies and Curiosities of Medicine
....But it is not only in relation to color that we find telegony to have been noticed in the human subject. Dr. Middleton Michel gives a most interesting case in the American Journal of the Medical Sciences for 1868: 'A black woman, mother of several negro children, none of whom were deformed in any particular, had illicit intercourse with a white man, by whom she became pregnant. During gestation she manifested great uneasiness of mind, lest the birth of a mulatto offspring should disclose her conduct. . . . It so happened that her negro husband possessed a sixth digit on each hand, but there was no peculiarity of any kind in the white man, yet when the mulatto child was born it actually presented the deformity of a supernumerary finger.
Telegony, Part 2 : Anomalies and Curiosities of Medicine