On a recent Thursday morning, Joseph Rosenthal, 77, drove from his barn-red, four-story house on Buena Vista Terrace to a lawyer’s office in the Castro, where he quietly transferred a substantial part of his estate to the endowment fund of the Horizon Foundation, a grant-giving organization for the gay, lesbian, bisexual and transgender community. “I have almost no family living at this time,” said Rosenthal, a retired librarian. “Certainly, not having children prompts one to consider other options, such as supporting charitable organizations in the area of my particular interest.” The lesbian, gay, bisexual and transgender movement has traditionally depended […]