As a matter of fact, breeders sometimes use "Teaser Toms" with their queens in oestrus, when they don't want them to bear another litter at that time, to prevent certain uterine conditions that sometimes arise under those conditions.
Teaser Toms are whole male cats that have been rendered sterile by a vasectomy. Since procreation is not intended, but instead, the "sexual satisfaction" of the queen, any almost any whole adult male cat may be used as a Teaser Tom, as long as he meets certain criteria. Previously sexually active males, such as retired studs, may be enlisted as Teaser Toms, as well as non-pedigreed males.
For the full scoop on this highly interesting subject, read "What is a Teaser Tom?" by Gail Pomerantz.