Telegony (pregnancy)

Telegony is a theory in heredity, now discredited but widely believed until the late 19th century, holding that offspring can inherit the characteristics of a previous mate of one or both parents.

The most widely cited example was Lord Morton’s Mare, cited by Charles Darwin. Lord Morton bred a white mare with a zebra stallion, and when he later bred the same mare with a white stallion, the offspring had strangely stripes in the legs.

Although August Weismann had expressed doubts about the theory earlier, it did not fall out of scientific favor until the 1890s, when a series of experiments by James Cossar Ewart in Scotland and other researchers in Germany and Brazil failed to find any evidence of the phenomenon. The result obtained by Morton could probably be caused by the display in the offspring of the recessive genes inherited by the Morton's mare from her parents/grandparents. 

In mammals, each sperm has the haploid set of chromosomes and each egg has another haploid set. During the process of fertilization a zygote with the diploid set is produced. This set will be inherited by every somatic cell of a mammal, with exactly half the genetic material coming from the producer of the sperm (the father) and another half from the producer of the egg (the mother, obviously). Thus, the myth of telegony is fundamentally incompatible with our knowledge of genetics and the reproductive process.

Still, the belief in telegony persists among some politically marginal groups, such as White supremacists in the Western world, as well as some other racists and/or religious fundamentalists, e. g., in Russia and other ex-USSR countries. For example, some White supremacists may argue that if a white woman has sex with an African-American man and produces a child of mixed parentage, then subsequently has sex with a white man, the second child will also be born with African-American physical characteristics.