Spermist is an old-fashioned term used to describe a person who believes that all living beings are derived solely from sperm. This theory was popularized in the 17th and 18th centuries but has since been disproven by modern science. If you are looking for an alternative term to describe this belief, you could use the word spermism, which means the same thing. Other terms that could be used include spermaticism, which is a belief in the paternal transmission of characteristics, or simply germ theory, which is the widely accepted scientific explanation for how organisms develop. Regardless of the terminology, the idea of spermism is now considered archaic and has little relevance to contemporary biology.