{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,2]],"date-time":"2026-04-02T18:45:11Z","timestamp":1775155511870,"version":"3.50.1"},"reference-count":30,"publisher":"Public Library of Science (PLoS)","issue":"4","license":[{"start":{"date-parts":[[2026,4,2]],"date-time":"2026-04-02T00:00:00Z","timestamp":1775088000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/publicdomain\/zero\/1.0\/"}],"funder":[{"DOI":"10.13039\/100005258","name":"National Center for HIV\/AIDS, Viral Hepatitis, STD, and TB Prevention","doi-asserted-by":"publisher","award":["U38PS004650"],"award-info":[{"award-number":["U38PS004650"]}],"id":[{"id":"10.13039\/100005258","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/100000060","name":"National Institute of Allergy and Infectious Diseases","doi-asserted-by":"publisher","award":["P30 AI027757"],"award-info":[{"award-number":["P30 AI027757"]}],"id":[{"id":"10.13039\/100000060","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/100009633","name":"Eunice Kennedy Shriver National Institute of Child Health and Human Development","doi-asserted-by":"publisher","award":["R24 HD042828"],"award-info":[{"award-number":["R24 HD042828"]}],"id":[{"id":"10.13039\/100009633","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["www.plosone.org"],"crossmark-restriction":false},"short-container-title":["PLoS One"],"abstract":"\n Background<\/jats:title>\n Relationships and recent sexual experience can impact sexual behaviors, networks, and STI testing. How they affect trends in these factors and increasing STI rates is understudied.<\/jats:p>\n <\/jats:sec>\n \n Methods<\/jats:title>\n We analyzed data from 28,027 females and 23,479 males ages 15\u201344 from the National Survey of Family Growth, 2008\u20132010 through\u00a02017\u20132019. We used survey-weighted linear or logistic regression to evaluate linear trends in self-reported sexual behaviors with opposite-sex partners; sexual network attributes; and STI testing, stratified by sex and, separately, by marital\/cohabiting status and number of past-year vaginal sex partners (1 vs.\u2009\u2265\u20092). Trends p\u2009<\u20090.050 reported below.<\/jats:p>\n <\/jats:sec>\n \n Results<\/jats:title>\n From 2008\u20132019, condom use at last vaginal sex decreased among never-married females (51.9% in 2008\u201310 to 42.9% in 2017\u201319), never-married males (61.9%\u221256.3%), and individuals with \u22652 partners (females\u2009=\u200945.3%\u221234.9%; males\u2009=\u200954.0%\u221245.7%). Mean number of vaginal sex acts in past 4 weeks decreased among cohabiting females (9.46\u20137.40), never-married males (4.11\u20133.40), and males with 1 partner (7.25\u20136.62). The proportion of never-married females reporting sex with males with male partner(s) increased from 2.5% to 5.1%; similarly, percentages of never-married males (3.8%\u22125.5%) and males with \u22652 partners (4.6%\u22126.3%) reporting sex with males increased. Racial\/ethnic homophily with current vaginal sex partners decreased among cohabiting females (86.5%\u221280.4%) and married and never-married males (married\u2009=\u200988.9%\u221285.9%; never-married\u2009=\u200981.2%\u221272.3%). Past-year chlamydia testing increased among females who were married (13.0%\u221217.1%), previously-married (27.6%\u221245.8%), or had 1 partner (21.7%\u221225.4%).<\/jats:p>\n <\/jats:sec>\n \n Conclusions<\/jats:title>\n Changes in sexual behaviors, network attributes, and STI testing from 2008\u20132010 through 2017\u20132019 varied by marital\/cohabiting status and number of past-year opposite-sex partners in complex ways, most commonly among never-married females and males and males with multiple partners. While these changes\u2019 combined potential impact on STI transmission is uncertain, understanding trends in sexual behaviors, networks, and testing by marital\/cohabiting status and partner number can contextualize their contributions to the STI epidemic and support sexual health services tailoring and prioritization.<\/jats:p>\n <\/jats:sec>","DOI":"10.1371\/journal.pone.0343813","type":"journal-article","created":{"date-parts":[[2026,4,2]],"date-time":"2026-04-02T17:46:16Z","timestamp":1775151976000},"page":"e0343813","update-policy":"https:\/\/doi.org\/10.1371\/journal.pone.corrections_policy","source":"Crossref","is-referenced-by-count":0,"title":["Changes in sexual behaviors, network attributes, and STI testing among 15\u201344-year-olds by marital\/cohabiting status and partner number: National Survey of Family Growth, 2008-19"],"prefix":"10.1371","volume":"21","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-7786-0194","authenticated-orcid":true,"given":"David A.","family":"Katz","sequence":"first","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Casey E.","family":"Copen","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Laura T.","family":"Haderxhanaj","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Matthew","family":"Hogben","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4334-958X","authenticated-orcid":true,"given":"Deven T.","family":"Hamilton","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"340","published-online":{"date-parts":[[2026,4,2]]},"reference":[{"key":"pone.0343813.ref001","unstructured":"Centers for Disease Control and Prevention. 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