The spermists believed that: the male made the only hereditary contribution to the offspring the male and female traits were blended in the offspring the female made the only hereditary contribution to the offspring the male and the female made equal contributions to the next generation

the male made the only hereditary contribution to the offspring.

Spermism was the one of the two models of theory of performationism, another one was ovism. The theory was predominant in the 17-18 century.  Spermist perfromationism was a believe that offsprings develop from tiny fully formed embryo contained inside the head of the male sperm. Therefore, it follows the notion that male is the only contributor of the hereditary information from parents to offsprings. Among the spermist philosophers some scientists like Nicolaas Hartsoeker, Wilhelm Gottfried Liebniz and Anton Leeuwenhoek are known.