The term "homophile" is favoured by some because it emphasizes love ("-phile" from Greek φιλία) rather than sex. The first element of the word, the Greek root "homo-", means "same"; it is unrelated to Latin "homo", "person". Coined by the German astrologist, author and psychoanalyst Karl-Günther Heimsoth in his 1924 doctoral dissertation "Hetero- und Homophilie", the term was in common use in the 1950s and 1960s by homosexual organizations and publications; the groups of this period are now known collectively as the homophile movement.