Polygamy is spreading in PNG

In Papua New Guinea, the proliferation of social problems related to polygamous marriages has led to one social justice advocate calling polygamy a “social evil”. It certainly leads to some serious problems. 65% of PNG’s female prisoners are convicted of a crime related to polygamous marriages, specifically, the murder of a fellow wife. Julie Soso, a female politician, proposed a bill in 2012 to outlaw polygamous marriages. In 2014, the Civil Registration Act was amended to make “bigamous or polyandrous” (sic) customary marriages illegal. (Polygamous formal marriages were already outlawed.)

Despite this, polygamous marriages, once concentrated in particular parts of the country and among particular social groupings, are becoming increasingly widespread in PNG. In this blog, we discuss five trends in polygamy based on the three Demographic and Health Surveys (DHSs) that have been carried out in PNG over the last 30 years: in 1996, 2006 and 2016-18 (referred to here as 2016).

First, the total share of married women in a polygamous relationship increased between 1996 and 2006 from 14% to 18%, and then stabilised between 2006 and 2016 (see Figure 1).

Second, and also as shown in Figure 1, polygamy used to be much more concentrated in rural areas. Now, it is equally prevalent in urban areas. Urban areas saw an increase of 9 percentage points in the proportion of women engaging in polygamous marriages (almost a doubling), compared to a 3 percentage point increase in rural areas since 1996.

Third, since 1996, polygamy has become less concentrated in the Highlands, and more of a national phenomenon. The three coastal regions traditionally known for monogamous marriages show a notable upward trend in polygamous marriages (Figure 2). In contrast, in the Highlands region, the share of women in polygamous marriages has stayed about constant.

Fourth, polygamy used to be most common among older women. In 1996, almost one-quarter of women aged 45-49 were in a polygamous relationship. That share has actually gone down, but the share of all other age groups has increased, and the gap between older and younger women has fallen. There is also a significant increase in the proportion of teenage women in a polygamous marriage, which was 7% in 1996 and is now 13%.

Fifth, uneducated women used to be almost twice as likely to be in a polygamous marriage as educated women. But according to the most recent data, an uneducated woman is now only 25% more likely than an educated woman to be in a polygamous relationship. Note that the category of educated includes those women with only an elementary and primary education, and that there is a higher proportion of women who are educated in the general population now.

To summarise, polygamy increased between 1996 and 2006 and then stabilised over the next decade. But over both decades, polygamy has become more widespread or evenly distributed. Polygamy used to be concentrated in the Highlands, in rural areas, among older and uneducated women. But it is now more evenly spread through all regions of the country, is as common in urban as in as rural areas and is less concentrated among older and uneducated women.

Polygamy is by now a huge part of life in PNG. According to the 2016 data, 19% of PNG’s married women – almost one in five – live in polygamous marriages. Not all women are married, so it is about 12% of all women. This is many more than the 3.3% of all men who report themselves to be in a polygamous relationship. Of course, the share of men must be smaller because it is nearly always polygyny (one husband and two or more wives), not polyandry (one wife and two or more husbands). But another factor is that the average man under-reports the extent of polygamy. According to the men surveyed in 2016-18, on average there are 1.08 wives for every husband, but according to the women, there are 1.25. In any case, polygamy affects far more men than the ones who engage in it. Because some men take more than one wife, more men than women will never get married. In the 2016-18 survey, 35% of women have no husband, but 46% of men have no wife.

Polygamy is also very common in Africa, but there it is declining. A 2022 study of 27 sub-Saharan countries also using DHS data and looking at about the same period found that in the first survey (1996) on average 29% of married women were in a polygamous relationship and in the second survey (2016) on average 21% were. There is no sub-Saharan African country where, as in PNG, polygamy has increased over the last 20 years. PNG’s polygamy rate has gone from half the sub-Saharan Africa average to very close to that average (18.8% vs 21.2%).

There are many theories of polygamy and its increased popularity in PNG. But, whatever the reasons for it, the data suggests that it is becoming more entrenched in PNG’s national life – increasing in importance and increasingly cutting across regional, urban/rural divides, social classes and age groupings.

Data Note: The 2016–18 DHS level data is made available by The DHS Program. The comparative statistics reported in this blog are available in the: 1996 DHS Report (Table 5.2); 2006 DHS Report (Table 5.2); and 2016–18 DHS Report (Table 4.2.1). For simplicity, we refer to the 2016–18 DHS (carried out over three years) as the 2016 DHS. Following this precedent, we use the better-known word ‘polygamy’ (more than one wife or husband) instead of less common, but more accurate ‘polygyny’ (more than one wife). While we refer to wives and husbands, the surveys also include non-married partners, so it would be more accurate to refer to partnered women and men. Finally, the surveys are of women and men aged 15-49.

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Kingtau Mambon

Kingtau Mambon is currently undertaking a Master of International and Development Economics degree at the ANU Crawford School of Public Policy, for which he was awarded a scholarship through the ANU-UPNG Partnership.

Stephen Howes

Stephen Howes is Director of the Development Policy Centre and Professor of Economics at the Crawford School of Public Policy at The Australian National University.


  • Hi Dr. Digim’Rina,

    Thank you for sharing your perspective. As you might have known, both qualitative and quantitative research methodologies have their own merits and demerits. The former is preferred in social science studies, which makes it conventional to use it for studies such as those of polygamous marriages, due in part to its depth and detail in capturing human experiences. However, this conventional preference does not negate the essential contributions of quantitative analysis. This study uses secondary data from the Demographic and Health Survey (DHS) and is quantitative by design.

    The importance of quantitative studies in the social sciences cannot be understated. While narrative case studies offer valuable insights into individual experiences, relying solely on them can lead to selective storytelling and anecdotal biases (1)(2). Statistics are essential for providing a comprehensive and objective overview of social and cultural behaviours. The use of DHS provides perspective on broader patterns, trends, and correlations across diverse populations of the entire country, which individual narratives cannot capture. Just by looking at the static figures in 2016–18, DHS does not tell us trends, or “how small is small,” or how certain phenomena in society have evolved over time. We might think that below 20% on average means polygamous marriages are less prevalent in the country, but it has actually moved up from 14%.

    Also, percentages should not be taken lightly. DHS studies women of age category 15-49 years who makes up 55.4% of the total women population of 5,638,974 in the country ie approximately 3, 123,991 women (3). 20% of this figure is around 624 798 women who lives in polygamous marriages (3). That’s almost 2x entire population of Western province or 3x entire population of Oro province or 8x entire population of Manus province (3). Simply put, for every fifth women you meet on the street, one of them has a shared husband. Also, while other regions, might have smaller proportion of polygamous marriages, the fact is-for the last almost 30 years, the trend has gone up (4)(5)(6). In essence, quantitative analysis is crucial for formulating policies, laws, and interventions that are based on experiences of the wider community and not a selected few.

    On your second concern, the data used in this study is mostly to “inform” and “not to moralise”. We clearly demonstrate that in the last paragraph: “There are many theories of polygamy and its increased popularity in PNG. But, whatever the reasons for it, the data suggests that it is becoming more entrenched in PNG’s national life, increasing in importance and increasingly cutting across regional, urban/rural divides, social classes and age groupings”.

    And let’s be aware that our own observations should not be generalised to the entire country. Judges who deal with settling disputes as their profession has called to end polygamous marriages (7). Around 65% of the total women’s population in prison have murdered fellow women whom they share a husband with (8). Think about the kids of the women in prison and the one being murdered—possibly struggling to survive. In a survey carried out across various regions of the country, Catholic anthropologist Ennio Mantovani found that approximately 70% of men and 90% of women believe that polygamy negatively affects their society (9). Even in the Highlands, where it is highly prevalent, two-thirds of the respondents utterly condemned it (9). Senior police officers even claimed that polygamy is one of the reasons why domestic violence is on the rise in PNG (9). A recent study shows that over 35% of intimate partner violence is driven by extramarital affairs (10), which is a precursor to polygamous marriages. While polygamous marriages are part of PNG culture (11) and seen as beneficial (12), in contemporary PNG, literature has shown otherwise (13)(14)(15)(16).

    (1) https://doi.org/10.1016/j.obhdp.2020.01.006
    (2) https://www.ucg.ac.me/skladiste/blog_609332/objava_105202/fajlovi/Creswell.pdf
    (3) https://www.nso.gov.pg/statistics/population/
    (4) https://pacific-data.sprep.org/resource/png-demographic-and-health-survey-dhs-report-1996
    (5) https://www.nso.gov.pg/wpfd_file/demographic-health-survey-2006-report/
    (6) https://dhsprogram.com/publications/publication-fr364-dhs-final-reports.cfm
    (7) https://www.looppng.com/png-news/judge-echoes-calls-look-polygamy-68601
    (8) https://femilipng.org/wp-content/uploads/National-Strategy-to-Prevent-and-Respond-to-GBV.pdf
    (9) https://www.dwu.ac.pg/en/images/All_Attachements/Research%20Journals/vol_08/2008-V8 6_Stollenwerk_Exploring_the_Roman_Catholic_Churchs_Stance_on_Polygamy_in_PNG.pdf
    (10) https://devpolicy.org/intimate-partner-violence-in-port-moresby-drivers-and-outcomes-20240118/
    (11) https://www.thenational.com.pg/polygamy-part-of-culture/
    (12) https://www.thenational.com.pg/arguments-for-and-against-polygamy/
    (13) https://www.thenational.com.pg/outlaw-polygamy-immediately/
    (14) https://www.thenational.com.pg/outlaw-polygamy-in-country/
    (15) https://www.thenational.com.pg/polygamy-today-begets-violence/
    (16) https://www.pngattitude.com/2019/01/practice-of-polygamy-has-become-a-destructive-force-in-png.html

  • I find it generally worrying when interpretations on certain human social/cultural behavior is heavily reliant on statistics. For a more nuanced presentation I’d rather that a few cases as narratives might suffice to help show the dynamics of how a polygamous (gynous/androus incl.) situation unfolds. And while on statistics, the PngNSO (2019 ) figures presents a relatively innocuous picture picture on ‘polgynous’ relationships in PNG [PNG National Statistics Office, (2019). Papua New Guinea Demographic and Health Survey 2016 – 2018: Port Moresby: NSO.]. In fact and aside from Morobe, Hela, EHP and SHP, most provinces reported instances below 20% of polygamous relationships. And by region, polygynous verses monogamous relationships ratio respectively show Momase at 24%, Highlands at 36% (over a third), Southern at 18%, and NG Islands at 22%. Monogamous relationships are therefore still dominant and household issues remain the same as with polygamous relations. Another worrying thing about the authors’ presentation is that it inherently and unfortunately carries moral undertones in that monogamous relations are seen in the ‘light’ whilst polygamous is in the ‘dark’. I do not think figures used by the authors suggest so however, they inadvertently imply so. I’ve come across enough offsprings that have done well through their polygamous upbringing and remain proud of their polygamous parents’ astute guidance as well. Generally speaking, global household issues are still dominated by monogamous relationships.

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