Table 1 Sample characteristics by sex behavior

School

 Peking University

66 (30.6%)

111 (20.2%)

177 (23.1%)

0.0238*

11.2582

 Peking Union Medical College

100 (46.3%)

263 (47.9%)

363 (47.5%)

 Capital Medical University

50 (23.1%)

175 (31.9%)

225 (29.4%)

Major

 Nursing

33 (15.3%)

177 (32.2%)

210 (27.5%)

< 0.001***

33.0492

 Clinical Medicine

78 (36.1%)

211 (38.4%)

289 (37.8%)

 Other Majors

105 (48.6%)

161 (29.3%)

266 (34.8%)

Academic Level

 Undergraduate

119 (55.1%)

467 (85.1%)

586 (76.6%)

< 0.001***

77.6862

 Graduate

97 (44.9%)

82 (14.9%)

179 (23.4%)

Age

  < 22

86 (39.8%)

395 (71.9%)

481 (62.9%)

< 0.001***

68.5739

  > = 22

130 (60.2%)

154 (28.1%)

284 (37.1%)

Biological Sex

 Male

93 (43.1%)

157 (28.6%)

250 (32.7%)

< 0.001***

14.7287

 Female

123 (56.9%)

392 (71.4%)

515 (67.3%)

Psychological Gender

 Male

92 (42.6%)

157 (28.6%)

249 (32.5%)

0.00727*

14.0084

 Female

121 (56.0%)

385 (70.1%)

506 (66.1%)

 Other

3 (1.4%)

7 (1.3%)

10 (1.3%)

Region

 Urban Area

150 (69.4%)

399 (72.7%)

549 (71.8%)

0.286

5.0102

 Town

35 (16.2%)

101 (18.4%)

136 (17.8%)

 Rural Area

31 (14.4%)

49 (8.9%)

80 (10.5%)

Family Type

 Nuclear Family

193 (89.4%)

486 (88.5%)

679 (88.8%)

0.998

1.0994

 Skip-Generation Family

4 (1.9%)

17 (3.1%)

21 (2.7%)

 Single-Parent Family

13 (6.0%)

29 (5.3%)

42 (5.5%)

 Remarried Family

4 (1.9%)

11 (2.0%)

15 (2.0%)

 Other

2 (0.9%)

6 (1.1%)

8 (1.0%)

Family Values

 Traditional

121 (56.0%)

340 (61.9%)

461 (60.3%)

0.656

2.4349

 Neutral

49 (22.7%)

113 (20.6%)

162 (21.2%)

 Open-Minded

46 (21.3%)

96 (17.5%)

142 (18.6%)

Monthly Living Expenses (CNY)

 1000 and Below

3 (1.4%)

19 (3.5%)

22 (2.9%)

< 0.001***

65.0563

 1000–1500

17 (7.9%)

117 (21.3%)

134 (17.5%)

 1500–2000

43 (19.9%)

171 (31.1%)

214 (28.0%)

 2000–2500

50 (23.1%)

123 (22.4%)

173 (22.6%)

 2500–3000

41 (19.0%)

61 (11.1%)

102 (13.3%)

 Above 3000

62 (28.7%)

58 (10.6%)

120 (15.7%)

Sexual Orientation

 Pansexual, Asexual, and Others

4 (1.9%)

40 (7.3%)

44 (5.8%)

< 0.001***

27.2687

 Heterosexual

174 (80.6%)

435 (79.2%)

609 (79.6%)

 LGB

19 (8.8%)

11 (2.0%)

30 (3.9%)

 Bisexual

19 (8.8%)

63 (11.5%)

82 (10.7%)

Sexual Attitude

 Positive

137 (63.4%)

279 (50.8%)

416 (54.4%)

0.0394*

10.0599

 Neutral

67 (31.0%)

224 (40.8%)

291 (38.0%)

 Negative

12 (5.6%)

46 (8.4%)

58 (7.6%)

Sexual Knowledge Level

 High (> 23)

130 (60.2%)

289 (52.6%)

419 (54.8%)

0.14

6.9165

 Medium (20–23)

46 (21.3%)

169 (30.8%)

215 (28.1%)

 Low (< 20)

40 (18.5%)

91 (16.6%)

131 (17.1%)