Table 1

Baseline characteristics of study participants

Factors	N	Per cent
Overall	797	100
Age (median, years)	28
Ethnicity
Han	738	92.6
Minority	59	7.4
Education
Less than high school	383	48.1
High school and above	414	51.9
Beijing permanent resident	149	18.7
Monthly income (median, US$)	294
Marital status in the past 3 months
Single	492	61.7
Married	141	17.7
Cohabiting with male or female sex partner	125	15.7
Separated or divorced or widowed	39	4.9
Sexual orientation
Homosexual	539	67.6
Heterosexual or bisexual	258	32.4
Age of sexual debut (median, years)	20
Age of homosexual debut (median, years)	25
Partner of sexual debut
Male	524	65.8
Female	273	34.2
Number of male sex partners in the past 6 months (median)	2
Bought or sold sex with male sex partners in the past 6 months	48	6.0
Had unprotected anal sex with regular male sex partners in the past 6 months	189	23.7
Had unprotected anal sex with casual male partners in the past 6 months	103	12.9
Had sex with female sex partners in the past 6 months	141	17.7
Had unprotected sex with female sex partners in the past 6 months	94	11.8
Used illicit drugs in the past 6 months	8	1.0
Had STD syndrome in the past year	137	17.2
Syphilis positive	131	16.4
HSV-2 positive	37	4.6