PG Diploma in Sexology and Psychosexual Counseling. For More Info WhatsApp- 9604715783/9359863878. From amongst several techniques that are used in behavior therapy, ‘systematic desensitization technique’ is used in sex therapy. Prior to 1970 sexual dysfunctions were managed by psychiatrists. After 1970, the Masters & amp; Johson model of sex therapy made it possible to treat sexual dysfunctions by psychologists, social workers, nurse, counsellors, and medical doctors.