Concurrent sexual partnerships (relationships that overlap in time) have been associated with the transmission of sexually transmitted infections (STI), including syphilis,1 chlamydial infection,2 and heterosexually acquired human immunodeficiency virus (HIV) infection.3 Although the rate of partner acquisition may be similar in concurrent compared to serially monogamous partnerships, the overlap of sexual partnerships can lead to faster spread and establishment of STIs in a population.3–6
Research concerning the sociocultural factors that influence the occurrence of concurrency has begun to emerge for some populations, such as the relationship between acculturation and sexual behavior among Hispanic youth.3,7,8 In addition, qualitative research has identified different concurrency patterns that may be associated with varying STI risk depending on partnership type (primary vs. nonprimary) and the likelihood of condom use with each concurrent partner.9 One pattern potentially associated with high STI risk involves concurrency in the context of a coparenting relationship.9 Coparenting concurrency involves engaging in sexual intercourse with a coparent while in another sexual partnership. Black, unmarried fathers report difficulty with ending a sexual relationship with the mother of their children despite not being in a mutually monogamous relationship with her. Furthermore, women in main partnerships with unmarried fathers reported sexual activity outside the relationship as more acceptable if it occurs with a coparent.9,10
To date, no published study has quantitatively examined coparenting in the context of concurrent sexual partnerships. We used data from male respondents in Cycle 6 of the National Survey of Family Growth (NSFG) to (1) calculate the overall and race-specific prevalences of coparenting concurrency; (2) describe coparenting concurrency patterns; and (3) determine demographic and behavioral correlates of coparenting concurrency.
The NSFG is a cross-sectional survey conducted by the National Center for Health Statistics designed to examine trends in contraception, marriage, divorce, sexual activity, and fertility.11 Cycle 6 of the NSFG was conducted in 2002 and was the first cycle to include men. In the US household population, men and women aged 15 to 44 years were targeted, and teens (aged 15–19), blacks, and Hispanics were oversampled.12 The survey collected data about demographic, socioeconomic, and behavioral characteristics and was administered by female interviewers using computer-assisted personal interviewing. More sensitive questions were administered using audio computer-assisted self-interviewing.12 In all, 78% of males sampled completed the interview, yielding a total of 4928 male respondents.12 We excluded 274 men who reported a race/ethnicity other than white, non-Hispanic black, or Hispanic from all analyses because only 12 men in this group engaged in concurrency resulting in a final sample of 4654 men.
Concurrent Sexual Partnerships
Concurrency with female partners was determined, as in previous research,3,13–15 by examining dates of first and last intercourse with each partner discussed during the interview. Reported dates of first sexual intercourse for up to 4 (current wife/partner and 3 most recent) sexual partners were ordered sequentially. Partnerships that ended 12 months before the interview were excluded. The dates of first and last sex for all partnerships were compared for men who provided information on 2 or more sexual partners.
For each partnership pair, the month of first sexual intercourse with the later partner was compared with the month of last sexual intercourse with the earlier partner. If the month of first sex with the later partner occurred before the month of last sex with the earlier partner, the partnership was considered concurrent. Coparents were defined as a man and woman who are the joint biologic parents of a child. For each sexual partner, a respondent was asked questions about children he coparented with the partner, including biologic, foster, adopted, and step children. Only biologic children were included in our coparenting definition, and biologic children from other partnerships that ended more than 12 months before the interview were not included. A concurrent partnership pair was classified as coparenting concurrency if the respondent had a biologic child with at least one of the concurrent sexual partners.
A conceptual model for the association between coparenting and concurrency was used to identify potential correlates of coparenting concurrency. Sociodemographic characteristics included age, race, educational attainment, and household income as a percent of the 2000 US poverty line. Sexual behaviors that affect the risk of STIs included the respondent's number of sexual partners (lifetime and in the past 12 months), frequency of condom use, and age at first sexual intercourse. Each respondent was asked about relationship characteristics, sexual activity, and fertility in relation to his reported sexual partners. We categorized incarceration for at least 24 hours as never, within the past 12 months, and greater than 12 months ago. Cohabitation status at the time of the child's birth and average relationship duration were used as proxy measurements for relationship quality.
All variables were coded as dichotomous or nominal categorical variables. All analyses were conducted using Stata version 10 (Stata Statistical Software: Release 10. College Station, TX) and incorporated the NCHS-provided sample weights and sampling design variables.12 We examined demographic, socioeconomic, fertility, and sexual behavior characteristics among all male respondents (N = 4654), all fathers (N = 1653), and all men with overlapping partnerships with women in the past 12 months (N = 430). We calculated the prevalence of coparenting concurrency, with 95% confidence intervals (95% CI) overall and by racial/ethnic group. We calculated χ2 statistics for bivariable associations of coparenting concurrency with sociodemographic and behavioral and relationship characteristics. Effect measure modification by race/ethnicity and age was examined using a product interaction model and a Wald test at the P < 0.20 significance level. Prevalence ratios and 95% CIs were calculated using a multivariable Poisson regression model including all covariates of interest and a race by age interaction term.
Differences between men engaging in concurrent partnerships and the entire NSFG sample have been described in detail in previous analyses.3 Approximately 18.0% of concurrent sexual partnerships among US men involved a coparent, and the overall prevalence varied slightly by race/ethnicity (Table 1). Black and Hispanic men who engaged in coparenting concurrency were considerably younger than white men who engaged in coparenting concurrency. Slightly more than a third of black men involved in coparenting concurrency were younger than 25 years, compared to 23% of Hispanic men and only 6% of white men (Fig. 1). The Wald P value for the interaction between race/ethnicity was 0.06 indicating prevalence ratio (PR) modification by race/ethnicity and age.
In a previous analysis of these data, it was estimated that 11% of the men had concurrent partnerships.3 Among this subset of 430 men, the prevalence of coparenting concurrency was highest among men with less than a high school education and decreased with increasing education (Table 1). The prevalence of coparenting concurrency among men with the lowest household incomes was almost 5 times the prevalence among men with the highest household incomes (39.7% vs. 8.4%). Coparenting concurrency prevalence was slightly higher among men who had children born outside marriage compared to men who did not but did not vary depending on the number of children born outside marriage (Table 1). Coparenting concurrency was more prevalent among fathers who had children with multiple partners (51.8%) than among fathers who did not have multiple partner fertility (12.5%).
Based on unadjusted PR and Wald tests (Table 2), age at interview, education, household income, condom use during the last month, cohabitation at the time of the child's birth, and average relationship duration were associated with coparenting concurrency. Among men who engaged in concurrent partnerships, those with an average relationship duration of 3 to 5 years were 5 times as likely to be involved in coparenting concurrency (PR: 5.23 [1.98, 18.83]) as those whose average relationship lasted less than 1 year. The association was even stronger for average relationship duration of 6 years or more compared to less than 1 year (PR: 13.79 [5.58, 34.10]).
The associations of coparenting concurrency with poverty, condom use, average relationship duration, and incarceration history persisted in the final, multivariable model (Table 2). Lower household income and increased relationship duration were associated with an increased likelihood of coparenting concurrency, with PRs increasing as household income decreased. Men who never used a condom were more likely to have engaged in coparenting concurrency in the past 12 months compared with men who always used a condom (PR: 1.88 [1.13, 3.12]). Having a history of incarceration, particularly incarceration within the past 12 months, was associated with a decreased likelihood of coparenting concurrency (PR: 0.54 [0.34, 0.85]).
Young black men (age 15–24) were more likely to engage in coparenting concurrency than white men, adjusting for sociodemographic characteristics, sexual and other high-risk behaviors, and relationship quality (Table 3). The largest racial differences in coparenting concurrency prevalence were observed among men aged 15 to 24 years. Compared to white men aged 15 to 24 years, black and Hispanic men were 4.60 (95% CI: 1.10, 19.25) and 3.45 (95% CI: 0.64, 18.43) times as likely to engage in coparenting concurrency. White men aged ≤35 were slightly more likely than black and Hispanic men to engage in coparenting concurrency.
This study is the first to explore quantitatively the role of coparenting relationships in concurrent sexual partnerships. Almost 1 in 5 men engaging in concurrent sexual partnerships with women in the past 12 months had a biologic child with at least one of his concurrent partners. Research among US men estimated concurrency was 3 and 2 times as likely among non-Hispanic blacks and Hispanics, respectively, compared with non-Hispanic whites.14 Data from our analyses do not suggest racial/ethnic differences in the overall prevalence of coparenting among men engaging in concurrency, though coparenting concurrency did vary considerably when examined jointly by race/ethnicity and age. The largest racial/ethnic disparities in coparenting concurrency prevalence were observed among men aged 15 to 24 with blacks and Hispanics being 4 to 5 times as likely to engage in coparenting concurrency as their white counterparts.
Results from this analysis highlight a potential population for which STI/HIV prevention messages could be developed. Young people (aged 15–24 years), including young parents, have been found to engage in a variety of risk behaviors, such as having multiple and concurrent sexual partners, unprotected intercourse, drug or alcohol use, and needle sharing.16–18 Inconsistent condom use was almost 4 times as likely among adolescent couples with a child compared to those without a child.19 Furthermore, young parents in relationships were generally unaware of their intimate partner's HIV testing history.20
Coparenting is generally discussed in the context of married couples, though it can occur in a number of different scenarios.21 Approximately 40% of all births in the United States in 2007 were to unmarried women, and the proportion of births to unmarried non-Hispanic black women (71.6%) was approximately 2.5 times as high as the proportion of births to non-Hispanic white women (27.8%).22 Relationships between unmarried parents are often unstable and characterized by repeated break-ups and reunions,23,24 creating an environment conducive to concurrency. In our analyses, births outside marriage were reported by over three-quarters (76.3%) of men engaging in coparenting concurrent partnerships, supporting the idea of increased concurrency among unmarried parents.
The term nonresident father includes a wide variety of men (e.g., divorced men who may or may not be remarried) but has more recently been used in research targeting nonresident fathers, regardless of marital status.25–27 Nonresident fathers' involvement with their children differs by race/ethnicity, and this difference can be partially explained by the status of the mother-father relationship.25 Specifically, minority nonresident fathers were more likely to maintain romantic relationships with their child's mother than white fathers, while mothers who had children with white men were more likely to repartner.25 Thus, it is possible that the coparenting relationship, particularly among unmarried racial/ethnic minorities, could impact the formation and persistence of concurrent sexual partnerships.
The trend toward coparenting concurrency's increased prevalence among white men age 35 and older compared to black and Hispanic men of the same age further highlights the importance of considering social contexts surrounding concurrent partnerships. Racial/ethnic differences in marriage and cohabitation may explain some of the observed differences in coparenting concurrency. Blacks in the United States are less likely than other racial/ethnic groups to marry,28 and among both men and women, unmarried individuals are much more likely to engage in concurrent partnerships than married individuals.13,28 Thus, one possible explanation is that occurrence of coparenting concurrency among young black and Hispanic men results from continued sexual activity with the coparent after initiation of a new, perhaps main, relationship. Conversely, among older white men, coparenting concurrency could be occurring in the context of an extramarital affair.
The cross-sectional nature of the data prohibited us from drawing causal inferences and must be acknowledged as a limitation. We were also not able to examine the contexts surrounding transitions into and out of sexual partnerships. Information on partnerships and children conceived in them was available for at most 4 sexual partners and only partnerships active during the past year. Men who had other partners could have had concurrent partnerships and children who were undetected. Additionally, sexual partnership dates were reported by month and year which could have introduced some ambiguity in determining concurrency status. For example, a sexual partnership that appeared to span 2 years could actually have consisted of one sexual act with a woman during 1 month and a second sexual act with the same woman 2 years later. Finally, the limited number of outcomes and a significant age by race/ethnicity interaction resulted in small cell counts, which decreased the precision of our effect estimates.
We defined coparents as a humans and woman who are the joint biologic parents of a child. This definition was more restrictive than that proposed in the sociology and child development literature, which includes coparents regardless of their sexual orientation or biologic linkage to the child.21 Though some instances of coparenting could have been missed by our more specific definition, the significance of a biologic child as a continuing manifestation of earlier sexual intimacy argues for differentiating adoptive and biologic children in examining coparenting concurrency.
Accuracy of self-report in this study depends on both recall and willingness to disclose sensitive information. The NSFG 2002 utilizes a life calendar approach to assist respondents in recalling information, but the potential for misreporting partnerships and/or dates remains. Self-report of sexual behaviors varies depending on the mode in which the survey is administered,29 and the use of audio computer-assisted self-interviewing likely improved the completeness of self-reported sensitive and high-risk behaviors.30–32 We have no evidence that reporting of sexual behaviors differed according to concurrency status.
Although the contextual factors that promote concurrency are not yet clear, they are likely to include a combination of imbalanced sex ratios, low marriage rates, economic differentials, media influences, and community and cultural norms. Our results show that the prevalence of coparenting concurrency differs by race/ethnicity and age and that this concurrency pattern is most prevalent among young black and Hispanic men. A comprehensive understanding of the types of concurrent sexual partnerships and the contexts in which they occur should provide a basis for more effective prevention interventions and public messages.
Coparenting relationships are complex and have profound implications for child health and development. Concurrent sexual partnerships add an additional layer of complexity to coparenting relationships, which can affect the health of the coparents, their other partners, and their community. Thus, future research should examine whether there is a link between coparenting concurrency and STI transmission. The concept of coparenting concurrency could be incorporated into STI studies by including questions on fertility histories and dates of sexual intercourse into data collection instruments. The importance of coparenting relationships in sexual networks warrants further investigation and could be beneficial in determining the role these relationships play in population-level STI dissemination.
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