State prosecutors on Thursday upgraded the charges to "unnatural offenses" and a felony charge.
Eighteen people were previously charged with "indecent practices". A magistrate set bail at around $3 500 each.
In 2008, President Yahya Jammeh told gays and lesbians to leave the country or have their heads cut off.
Gays and lesbians face threats of violence and discrimination across the continent.
In western Africa, legislators in Liberia and Nigeria are also trying to pass laws that would increase the legal penalties for homosexuality in those countries.