One of Beatty's students, Richard Hancock, found in 1974 that when anti-cock sperm antisera were added to rabbit semen used for insemination, the proportion of male offspring was significantly reduced. This work was in response to the findings of I.A Burkov (1968), who suggested that antibodies to cock sperm would react selectively with Y-bearing rabbit sperm. As an invention which could separate male- and female- determining spermatozoa was potentially of wider commercial interest, a patent was applied for by Beatty to protect this work (known as 'Control of Sex Ratio in Mammalian Offspring') before Hancock submitted his results for publication. In 1976, funding was also received from the Scottish Milk Marketing Board to determine whether the sex-ratio control method could be applicable in cattle. A United States Patent Application was also put forward in 1977.