The soul is not transmitted with the semen, but is created afresh with each man.
 Bertrand Russell, A History of Western Philosophy (1945). copy citation

Context

“The whole soul is present entire in every part of the body. The souls of animals, unlike those of men, are not immortal. The intellect is part of each man’s soul; there is not, as Averroes maintained, only one intellect, in which various men participate. The soul is not transmitted with the semen, but is created afresh with each man. There is, it is true, a, difficulty: when a man is born out of wedlock, this seems to make God an accomplice in adultery. This objection, however, is only specious. (There is a grave objection, which troubled Saint Augustine, and that is as to the transmission of original sin.” source