Ethel Person, Who Studied Sexual Fantasies, Dies at 77 Ethel Person, a Columbia University psychiatrist who did pioneering research on sexuality, visiting sex shops and drag dance clubs to help herself understand what motivates transsexuals and transvestites, and conducting broad-based clinical studies on the role of sexual fantasy in people's lives, died on Tuesday at her home in Manhattan. She was 77. The cause was complications of Alzheimer's disease, her son Lloyd Sherman said. Dr. Person wrote frequently on love and sexuality for general-interest publications and was the author of four books, the best known of which is "By Force of Fantasy: How We Make Our Lives" (1995), in which she argued that people shaped their lives by trying consciously or unconsciously to live out their fantasies. Eric Marcus, a former student of Dr. Person's and now the director of the Columbia University Center for Psychoanalytic Training and Research, which Dr. Person led from 1981 to 1991, said she was the first to do an "epidemiological study of sexual fantasy," in contrast to the scientist Alfred C. Kinsey's studies of sexual acts. "She was one of the early ones to say even human sexuality is not a biological occurrence," Dr. Marcus said in an interview. "Freud wrote that we are born with drives, but she said, "Yes, but they are malleable over time." " A few years after joining the staff of the psychoanalytic center, Dr. Person teamed with Dr. Lionel Ovesey, who would become a well-known authority on male homosexuality, to examine the largely unstudied question of how transsexuality and transvestitism develop. She ventured far beyond the clinical setting to pornography shops and underground clubs. "I remember the first time a guy dressed as a woman asked me to dance," she recalled in a 2003 interview with The New York Times. I felt his breasts poking me through his dress. That was a moment of truth for me. I wasn't put off or frightened. That's not ever something you know ahead of time - you can only find out when you do it. Her work, upsetting the conventional thinking, found that many transsexuals and transvestites did not perceive themselves as homosexuals but rather saw themselves in many different lights - sometimes, for example, as a woman trapped in a man's body, and sometimes as a heterosexual who preferred a feminine demeanor. Her theories have come to be widely accepted, said Kenneth J. Zucker, who leads the child and adolescent gender identity clinic at the Centre for Addiction and Mental Health in Toronto. "Her work suggested there were subtypes or different pathways," he said, "and that has absolutely been confirmed by other researchers." Dr. Person translated her academic work on sexuality into formats accessible to the general reader. In an article in 1988 in The Atlantic Monthly, she examined love triangles; in an interview in Oprah Winfrey's magazine, O, in 2004, she discussed what it takes to love. She was an early advocate of teaching women about how their sexual needs can be separate from those of their partners. Ethel Jane Spector was born in Louisville, Ky., on Dec. 16, 1934, to Louis Spector and the former Anna Zimmerman. Her home life provided some grounding for her future work: her father owned a speakeasy, where she spent many hours watching uninhibited, alcohol-fueled, sexually charged behavior; her mother, unusually for her time, was a mathematician with a master's degree; and her maternal grandfather owned a bookstore, which was a gathering place for the local intellectuals. Her father died when she was 12. After high school, she attended the University of Chicago, where she earned a bachelor's degree in 1956. She received her medical degree in 1960 from the New York University College of Medicine. Dr. Person's first marriage, to Allen Person, an engineer, ended in divorce after 10 years. In 1968 she married Barry Sherman, a psychiatrist, with whom she had two sons. He died in 1976. Two years later she married Stanley Diamond, a lawyer, who died in 2009. Dr. Person long held that no relationship was a failure if you learned something about yourself from it. In that spirit she kept every husband's name, her son Lloyd said. At her death she was officially Ethel Jane Spector Person Sherman Diamond, although she continued to use Person professionally. In addition to Lloyd Sherman, she is survived by another son, Louis Sherman; two stepdaughters from her third marriage, Nancy and Jessica Diamond; a grandchild; and three step-grandchildren.