Progenation was a method of artificial reproduction from a single organism wherein one parent is biological mother and father. It involves taking a sample of diploid cells, splitting them into haploids, then recombining them in a different arrangement and then growing the result into an offspring. During the Human-Hath War on the planet Messaline, both the Human and Hath factions used progenation machines to generate their armies. The progenation machines used in that conflict were able to create and grow a new offspring in a matter of moments. (DW: The Doctor's Daughter)
Interestingly, the mark left on the Doctor's hand was identical in shape, size, and location to the scar on the back of the [[Empty Child]'s hand.