title: A new perspective on sexual mixing among men who have sex with men by body image.
abstract: BACKGROUND
  "Casual sex" is seldom as non-selective and random as it may sound. During each sexual encounter, people consciously and unconsciously seek their casual sex partners according to different attributes. Influential to a sexual network, research focusing on quantifying the effects of physical appearance on sexual network has been sparse.
  
  
  METHODS
  We evaluated the application of Log odds score (LOD) to assess the mixing patterns of 326 men who have sex with men (MSM) in Hong Kong in their networking of casual sex partners by Body Image Type (BIT). This involved an analysis of 1,196 respondents-casual sex partner pairs. Seven BITs were used in the study: Bear, Chubby, Slender, Lean toned, Muscular, Average and Other.
  
  
  RESULTS
  A hierarchical pattern was observed in the preference of MSM for casual sex partners by the latter's BIT. Overall, Muscular men were most preferred, followed by Lean toned while the least preferred was Slender, as illustrated by LOD going down along the hierarchy in the same direction. Marked avoidance was found between men who self-identified as Chubby and men of Other body type (within-group-LOD: 1.25-2.89; between-group-LOD: <-1). None of the respondents reported to have networked a man who self-identified as Average for casual sex.
  
  
  CONCLUSIONS
  We have demonstrated the possibility of adopting a mathematical prototype to investigate the influence of BIT in a sexual network of MSM. Construction of matrix based on culture-specific BIT and cross-cultural comparisons would generate new knowledge on the mixing behaviors of MSM.
authors.affiliation: Stanley Ho Centre for Emerging Infectious Diseases, The Chinese University of Hong Kong, Hong Kong, China.
authors.forename: Ka-Kit
authors.initials: KK
authors.lastname: Leung
authors.affiliation: Stanley Ho Centre for Emerging Infectious Diseases, The Chinese University of Hong Kong, Hong Kong, China.
authors.forename: Horas T H
authors.initials: HT
authors.lastname: Wong
authors.affiliation: Stanley Ho Centre for Emerging Infectious Diseases, The Chinese University of Hong Kong, Hong Kong, China.
authors.forename: Claire M
authors.initials: CM
authors.lastname: Naftalin
authors.affiliation: Stanley Ho Centre for Emerging Infectious Diseases, The Chinese University of Hong Kong, Hong Kong, China.
authors.forename: Shui Shan
authors.initials: SS
authors.lastname: Lee
mesh_terms: D000328:Adult; D001828:Body Image; D018451:Homosexuality, Male / Q000523:psychology*; D006801:Humans; D008297:Male; D012747:Sexual Partners