Age mixing in sexual partnerships among young women




The number or percent of female respondents aged 15-24 years who have had sex with a non-marital, non-cohabiting partner who was 10 or more years older than themselves.

Age mixing, age-disparate, intergenerational and cross-generational are terms that are used interchangeably to describe significant age differentials in relationships. Some researchers have expanded the definition to an age difference of five years because the smaller gap has also been clearly associated with increased risk of HIV transmission in young women (Hope, 2007). Demographic and Health Surveys (DHS) AIDS modules further define intergenerational sexual relationships as non-marital. Evaluators will want to make this distinction.

Since this indicator does not specify a time period when the partnerships have occurred, evaluators may want to specify if the relationships have taken place within a certain timeframe, such as the last 12 months.

As a percentage, this indicator is calculated as:

(Number of female respondents aged 15-24 years who have had sex (within timeframe) with a partner 10 or more years older than themselves / Total number of female respondents aged 15-24 surveyed who have had sex (within timeframe)) x 100

Data Requirements:

Self-reported data from survey respondents


In a general population survey respondents are first asked whether they have ever had sex. Those who answer in the affirmative are asked whether any of their partners were at least 10 years older than themselves.

Age mixing is culturally acceptable in many places, but taboo in others. When asking about this indicator evaluators will want to be sensitive to the particular context and ask the questions in an appropriate, sensitive way.

This indicator can be disaggregated for age groups 10-14, 15–19 and 20–24 year , in school/out of school status, as well as by urban and rural populations.

Data Sources:

UNAIDS general population survey; DHS AIDS mod­ule; FHI BSS (adult); self-reported responses from interviews with youth



Intergenerational sex has been practiced for centuries and is quite common in many communities and cultures in the developing world.  However, there has been an increased interest in age mixing in sexual relationships due to the feminization of the AIDS epidemic and evidence that age mixing has been shown to be one of the factors in the spread of HIV (Hope, 2007). Young women 15-24 in sub-Saharan Africa are three times more likely to be infected with HIV than young men of the same age (UNAIDS, 2006). There is a growing collection of research demonstrating a significant association between age and economic disparities, risk behaviors and HIV infection (Luke, 2002).

Older men are more likely to have (and have had) multiple partnerships, thus increasing their chances of contracting and spreading HIV to their partners (Hope, 2007). Growing evidence also shows that men who have sex with younger women engage in higher levels of risky sexual behavior than other men of the same age group (Evans, Delva and Pretorius, 2010). Young women are sometimes forced into these relationships while others actively pursue older male partners. No matter their level of volition younger women are expected to be obedient and respectful toward older men, which undermines their ability to resist older men’s advances and negotiate condom use.  Physiological reasons also make it more likely for younger women to become infected with HIV. For these reasons, each sexual act with an infected man carries a higher risk of infection for a young girl. (UNAIDS, 2004).  It also carries the risk of contracting other sexually transmitted infections (STIs) and unwanted and early pregnancy.

A related indicator is Number of youth who have reported receiving money or other form of exchange for sex, as cross-generational relationships often have a transactional component. A review of over 45 studies of cross-generational sex found a transactional component to sexual relationships for adolescent girls who were not engaged in commercial sex work (Feldman-Jacobs, 2008).



One limitation of this indicator is that people often do not know their sex partner’s age. This is more likely to be true of casual partners than of spouses. In addition, the age difference constituting an elevated risk of exposure to HIV is not precisely known. When uncertain about a partner’s age, heaping or age clustering may occur, which is when respondents round up or down to a multiple of five or 10 (i.e. 15 or 20), which may distort the indicator. It should be noted, however, that the biases introduced through age clustering or age misreporting are unlikely to change greatly over time, so this may be of little consequence when time trends are being examined (WHO, 2004).

This measure cannot give an exact picture of patterns of age-mixing and does not show small changes in age gaps between partners. Nevertheless, it should show major changes in age-mixing of interest to HIV prevention and life skills programs, since women are unlikely to mistake a peer for a man much older than themselves. If women increasingly choose to have sex with their peers rather than with older men, or if older men become less likely to seek out substantially younger partners, these changes will be reflected in the indicator, regardless of errors in age-reporting (WHO, 2004).

Gender Implications:


Despite the risks involved with sexual relationships between older men and younger women, there are deeply rooted, gender-based cultural norms and personal motivations for why this practice is so common in many parts of the world. Young women’s motivations to be with older men are numerous and varied in different contexts. According to Luke and Kurz, the main motivation for cross-generational sex is financial gain, however finding a suitable marriage partner, wanting love and affection, and upward social mobility can also play a role. Girls often have fewer opportunities than older women and less access to pocket money from parents than boys, however there is an economic value to sex (Luke, 2002). In Ethiopia for example, young women described relationships with other men as “business opportunities” (Hope, 2007).

Older men seek younger women for a variety of reasons as well. Studies suggest enhanced prestige, enhanced access to sex on a regular basis, and domestic help. Further societal views on masculinity and polygamy perpetuate acceptability that men need multiple sexual partners in order to meet their desire for sexual gratification (Hope, 2007).

Family and societal pressures can make it normative for girls in sub-Saharan Africa, in particular, to engage in intimate relationships with older men (Luke, 2002).  In southern Africa, girls are encouraged to seek older men as partners and husbands because they are believed to be more stable partners than younger men. In other cases, girls are pushed into sexual relationships with older men by their families in order to earn income for the household.

The most common form of intergenerational sex occurs within marriages (Feldman-Jacobs, 2008) where it is also likely that husbands will transmit the disease to their wives because marital relationships are associated frequent sexual intercourse, greater exposure to infection and decreased likelihood of condom use (Luke 2002).

While cross generational sex is not stigmatized for men, it generally is for the young women they are involved with and thus girls might be hesitant to report being part of the relationship.



Evans J., Delva W. and Pretorius C.  2010. “Condom use among young Swazi in mixed-age relationships.”  Exchange on HIV and AIDS, Sexuality and Gender.  Royal Tropical Institute, Accessed on July 30, 2011.

Feldman-Jacobs C., Worley H. 2008. Cross-Generational Sex: Risks and Opportunities, Population Reference Bureau (PRB).

Luke N., Kurz K.M. 2002. Cross-generational and transactional sexual relations in Sub-Saharan Africa: Prevalence of Behavior and Implications for negotiating safer sexual practices. ICRW and PSI as part of the AIDSMark Project.

Hope R. 2007.  Addressing Cross-Generational Sex: a Desk review of research and programs. (Washignton DC: Population Reference Bureau PRB

National AIDS programmes: a guide to indicators for monitoring and evaluating national HIV/AIDS prevention programmes for young people. World Health Organization. 2004 ISBN 92 4 159257 5.