Skip to main content
. Author manuscript; available in PMC: 2019 Jul 31.
Published in final edited form as: Perspect Sex Reprod Health. 2017 Mar 2;49(1):55–67. doi: 10.1363/psrh.12020

Table 3.

Distribution of sexual initiation indicators within sexual initiation latent classes, by biological sex

FEMALES (n=1,628)

Typical Debut
% (n)
Dual Behavior Debut
% (n)
Early Sexual Debut
% (n)
Delayed Debut with Oral Sex
% (n)

Class size 41.4% (655) 34.8 (564) 17.4 (293) 6.4 (116)

Number of types of sexual acts, mean 2.7 2.6 2.8 1.6
Timing of first sexual encounter, mean age (yrs) 15.3 16.36 13.25 18.14
Anal sex Before age 18, %(n) 14.8 (74) 0 27.9(83) 0
Spacing Between 1st and 2nd Behaviors, (yrs)
    Multi-behaviors 14.8 (74) 100 0 0
    1 40.8 (261) 0 14.6 (51) 8.1 (12)
    2 28.4 (198) 0 7.6 (19) 7.7 (9)
    3–5 11.3 (89) 0 56.5 (156) 12.0 (13)
    6+ 4.6 (33) 0 21.3 (67) 17.7 (15)
    Single lifetime 0 0 0 54.6 (67)
First sexual behavior, %(n)
    VI first 58.1 (407) 0 87.8 (256) 20.2 (30)
    OS first 27.1 (174) 0 11.1 (30) 79.8 (85)
    AI, no VI <0.1 (≤3) <0.1 (≤3) 1.1 (7) <0.1 (≤3)
    VI/OS 8.4 (46) 95.8 (544) 0 0
    AI/VI 6.3 (26) 4.2 (19) 0 0

MALES (n=526)

Single Behavior Debut
% (n)
Multi Behavior Debut
% (n)
Early Anal Sex
% (n)
Very Early Debut
% (n)

Class size 50.4 (273) 32.3 (169) 11.2 (52) 6.2 (32)

Number of types of sexual acts, mean 2.3 2.5 2.6 2.8
Timing of first sexual encounter, mean age (yrs) 16.3 17.9 14.0 10.0
Anal sex Before age 18, %(n) 11.0 (29) 0 100.0 56.9 (16)
Spacing Between 1st and 2nd Behaviors, (yrs)
    Multi-behaviors 0 99.8 (168) 91.2 (47) 0
    1 37.1 (96) 0 3.6 (≤3) 8.2 (≤3)
    2 19.0 (62) 0 0 4.8 (≤3)
    3–5 23.0 (21) 0 2.3 (≤3) 5.9 (≤3)
    6+ 6.7 (21) <0.1 (≤3) 0 76.4 (25)
    Single lifetime 14.2 (33) 0 3.0 (≤3) 4.7 (≤3)
First sexual behavior, %(n)
    VI first 23.0 (81) 0 0 1.0 (≤3)
    OS first 75.7 (189) 0 0 80.8 (26)
    AI, no VI 1.3 (≤3) 12.6 (25) 55.5 (29) 18.2 (4)
    VI/OS 0 81.6 (135) 35.1 (17) 0
    AI/VI 0 5.8 (9) 9.4 (6) 0

VI= Vaginal Intercourse; OS= Oral Sex; AI= Anal Intercourse

All column percentages weighted to reflect Add Health complex sampling design; all N’s are unweighted counts. Cells with counts ≤3 reported as such due to Add Health reporting requirements. Percentages may not add to 100% due to rounding and/or weighting.