That is true. Some made by birth, some made by nurture, some made by individual or societal decision, some permanent, some who switch teams, and some who play both teams.
Still not sure if it is a "gay gene" or some environmental influence on the developing embryo, but there is a hereditary nature to psychological and emotional dispositions in families. (Can you tell we've got one in ours?)
Aside from homosexuality there are other instances of identical twins where one has an anomaly, personality trait, or whatever you want to call it...that the other genetic twin does not share. It cannot be said that every embryo, even if genetically identical, experiences exactly the same circulatory, hormonal and other pre-birth experience.