membership practices of social fraternities and sororities are exempt from Title IX in section (A)(6)(a). The U.S. Department of Education (DOE) regulations adopted pursuant to Title IX also allow such an exception for "the membership practices of social fraternities and sororities." (34 C.F.R. Sec. 106.14(a)). Prior to Title IX, many professional fraternities were all male and most professional sororities/women's fraternities were all female. Several of these professional fraternities and sororities even considered themselves both professional and social organizations because they often emphasized the social aspects of their activities. During the ensuing years since the enactment of Title IX, single-sex professional fraternities and sororities became coeducational to conform to Title IX. Several organizations simply opened their membership both men and women. For example, Phi Chi (medicine) opened membership to women in 1973; Phi Beta (music and speech) opened membership to men in 1976; and Delta Omicron (music) opened membership to men in 1979. A few single-sex groups merged with other organizations, such as Phi Delta Delta, a women's professional law fraternity, merged with Phi Alpha Delta (law) in 1972. Despite the fact that Title IX was enacted in 1972, there continues to be professional fraternities and sororities or their chapters that have not become coeducational and therefore, do not conform to Title IX. Generally, these groups still claim to be both professional and social organizations, for instance, Alpha Gamma Rho (men in agriculture), Alpha Omega Epsilon (women in engineering), and Sigma Phi Delta (men in engineering). Several social fraternities and sororities have membership practices of selecting their members primarily from students enrolled in particular majors or areas of study, including Phi Mu Alpha Sinfonia, Phi Sigma Rho, and Triangle. Nevertheless, these groups are social, rather than professional, organizations. Although they select members from students in a particular field of study, like a professional fraternity, they are single-sex social organizations because their purposes focus only on the social development of their members. Examples of groups that have been officially granted exemption from Title IX by the DOE to remain single-sex include Sigma Alpha Iota in 1981 and Phi Mu Alpha Sinfonia in 1983. Umbrella organizations Many professional fraternities, particularly those of the highest esteem and reputation, are members of the Professional Fraternity Association (PFA). This group resulted in 1978 from a merger of the Professional Interfraternity Conference (PIC) (for men's group) and the Professional Panhellenic Association (PPA) (for women's groups). In 2013,