The theory that human beings are of two different races, a male race and a female race. It was an idea put forward by British engineer, William H. Smyth in 1927 in Did Man and Woman Descend from Different Animals? It was picked up by an eccentric English antifeminist, Arabella Kenealy who developed it in The Human Gyroscope (1934). She explained the separate sexes and the essential maleness and femaleness of all the universe from atoms to galaxies as caused in some way by the gyroscopic effects of rotational motion. So, on Earth, northern peoples are more masculine than southern, the difference resulting from the greater gyroscopic effect nearer the equator, the difference in motion that makes Earth bulge a little at the equator, flatten at the poles an oblate spheroid. It is not a theory that has gained much support.