Why Aren’t Young People Getting Married Anymore? (1): Causes of Declining Marriage Rates through the Lens of Family Sociology

Why are so many young people choosing not to get married these days?

Some might point to internal or psychological shifts such as increasing individualism or changing views on love and marriage. Others may recall buzzwords like “Herbivore Men" (young Japanese men who are not aggressive in pursuing romantic relationships or career advancement) or “Parasite Singles.” Still others may link the trend to broader economic and labor-related changes, such as Japan's so-called “Lost Decades” or the impact of the “Employment Ice Age Generation" (people who entered the job market in the 1990s and early 2000s, when the economy was stagnant after the burst of the bubble economy). Because this is such a relatable issue, people often draw from their own experiences and intuitions to explain it. But what explanations have been offered from an academic perspective? Over the next three installments, we’ll explore this question together. In this first part, we’ll look at the causes of the decline in marriage rates as explored in family sociology.

• What Are Delayed and Non-Marriage?
• Value Shifts and Fertility Decline in Western Europe
• Has a Similar Shift in Values Occurred in Japan?
• Issues Yet to Be Fully Examined

What Are Delayed and Non-Marriage?

When rephrased in more academic terms, the question "Why are young people not getting married?" becomes: "Why are delayed marriage and non-marriage increasing?"

Delayed marriage refers to a rise in the average age at which people marry, resulting in a longer period of singlehood. Non-marriage indicates a growing proportion of individuals in each age group who remain unmarried, leading to a rise in the lifetime unmarried rate—the percentage of people who have never married by age 50 (『現代社会学事典』『家族社会学事典』).

Japanese family sociologist Masahiro Yamada has analyzed shifts in average age at first marriage and fertility rates, and identified five distinct phases of change  (山田2007:64).

⓪ 1945-50: Post-war confusion followed by a baby boom
① 1950-55: A rapid decline in births
② 1955-75: A period of stability in marriage and childbirth
③ 1975-95: Gradual rise in non-marriage
④ 1995-present: Rapid increase in non-marriage and decrease in the number of children per couple

In Japan, after the immediate post-war baby boom (⓪), the country transitioned from high birth and death rates to a stage of low fertility and mortality (①), followed by a stable period for marriage and childbirth (②). During this time, the lifetime unmarried rate (the proportion of people unmarried at age 50) remained around 2% for both men and women. The average age at first marriage also stabilized around 27 for men and 24 for women, and the typical pattern involved having two children after marriage. This period from 1955 to 1975 overlapped with Japan’s era of rapid economic growth, and the so-called "Baby Boomer Generation" largely followed this life course.

However, starting around 1975 (③), both the average age at first marriage and the proportion of unmarried individuals began to rise. Figure 1 below illustrates this trend, showing the increase in unmarried rates across all age groups since 1980. By 2020, the lifetime unmarried rate had climbed to 26.6% for men and 16.5% for women. In addition, according to the Ministry of Health, Labour and Welfare, the average age at first marriage in 2024 reached 31.1 years for men and 29.8 years for women, indicating a continuing trend of delayed marriage (厚生労働省2025).

Figure 1. Unmarried Rate by Age Group Over Time

(Source) 2023 edition of the Ministry of Health, Labour and Welfare White Paper, p.8 (令和5年版『厚生労働白書』p.8)

The reason non-marriage is viewed as a problem in Japan is that it is considered a major contributing factor to the country’s declining birthrate (廣嶋 2000; 岩澤 2002, 2008, 2015; 筒井 2023). Two main elements influence fertility trends: the marriage rate (the proportion of people who are married) and the marital fertility rate (how many children are born to married couples). While the marital fertility rate has not shown a significant decline in the past, recent years have seen some decrease. Nevertheless, it is clear that the decline in the marriage rate—that is, the increase in non-marriage—has played a significant role in driving down fertility levels.

Of course, the decision to marry or not is a personal choice, and not something others should interfere with. However, when viewed from a societal perspective, non-marriage is a key driver of low fertility—and with it, population aging—both of which are critical challenges for Japan. For this reason, extensive research has been conducted to explore the factors behind the rise in non-marriage.

Value Shifts and Fertility Decline in Western Europe

Declining birthrates have become a common trend across nearly all advanced nations. In Western European countries, fertility rates began to drop almost simultaneously in the late 1960s, and by the 1980s had fallen below the replacement level—the rate required to sustain population size—where they have largely remained stagnant ever since.

However, in Western Europe, non-marriage is not considered a primary cause of fertility decline. This is because childbirth and marriage have become decoupled in those societies. In that sense, the circumstances in Japan differ significantly from those in Western Europe.

In Western Europe, fertility decline has been attributed to a broader shift in social values. Traditional norms and moral expectations surrounding sexual behavior, cohabitation, marriage and divorce, and childbirth have weakened, giving way to the pursuit of individual self-fulfillment as the most important personal goal. Demographer Ron Lesthaeghe refers to this transformation as a process of secularization and individuation (Lesthaeghe & Surkyn 1988).

As a result, there has been a rise in divorce rates, an increase in non-marital cohabitation, and a growing number of births among cohabiting couples. Notably, “cohabitation” in this context is not seen as merely a prelude to marriage, but rather as a long-term alternative to it. In many Western countries, over 30% of children are born outside of marriage. In these societies, marriage and childbearing are no longer inseparable (J.M. Raymo 2022).

This value-driven transformation and its impact on fertility are captured by the Second Demographic Transition (SDT) theory. According to this theory, fertility decline is not just temporary but structural and irreversible, driven by profound changes in individual values. While the SDT theory has been the subject of criticism, it remains widely accepted as a framework for understanding fertility decline in Europe (河野 2007).

Has a Similar Shift in Values Occurred in Japan?

So, can Japan’s declining birthrate be explained in the same way as in Western Europe—as a result of shifting values? Does the Second Demographic Transition (SDT) theory also apply to Japan?

Demographer Retherford has argued that in Japan, changes in population trends tend to occur before shifts in values, and that the fertility decline observed in the 1970s was driven by socioeconomic factors rather than cultural or attitudinal change (Retherford 1996). According to his findings, the SDT framework may not be applicable to Japan.

That said, this does not mean that no value shifts have occurred in Japanese society. Retherford also noted changes in attitudes regarding women’s social participation and their roles in society.

Japanese demographer Makoto Atoh similarly observed a gradual move toward individualism in the postwar period. He points to a sharp decline in the belief that daughters are obligated to care for elderly parents, a weakening of traditional gender-role attitudes, and a significant rise in the perceived social value of women. These suggest that major changes have occurred in how women’s roles are viewed. However, Atoh also stresses that unlike in Western societies, Japan has not experienced a comprehensive breakdown of traditional values or a full embrace of individualism (阿藤 1997).

More recent studies also highlight the differences between Japan and Western countries in terms of value change. The core features of the SDT in Western Europe—such as the decoupling of marriage and childbirth, the rise of cohabitation as an alternative to marriage, and a significant increase in births outside of marriage—are largely absent in Japan (J.M. Raymo 2022).

In Japan, sociologist Masahiro Yamada once popularized the term “Parasite Singles” to describe unmarried young adults living with their parents (山田 1999). In his work, Yamada points out that despite drastic socioeconomic changes, traditional views on marriage—such as the idea that marriage transforms a woman’s identity or the preference for hypergamy (marrying “up”)—have remained relatively intact. In other words, although the economic landscape has changed, fundamental attitudes toward marriage have been slow to evolve.

Taken together, these studies suggest that Japan has not undergone the kind of deep value transformation seen in Western societies that contributed to their fertility decline. At the very least, there is little evidence to support the idea that changes in values alone can explain the rise in non-marriage in Japan.

Issues Yet to Be Fully Examined

However, the relationship between values and fertility is not as straightforward as it might seem.

As noted earlier, Retherford argued that value changes did not significantly influence fertility trends in the 1970s. At the same time, however, he suggested that the inverse may also be true: that fertility decline itself could lead to changes in values. In other words, rather than value shifts influencing fertility alone, the reverse dynamic is also possible—fertility changes may reshape social values. Moreover, these newly formed values may in turn accelerate further declines in fertility (Retherford 1996). This possibility requires further empirical investigation.

In addition, the social advancement of women since the 1970s—and the accompanying shifts in how society perceives women’s roles—must not be overlooked. As discussed in the previous section, many studies have highlighted changes in values related to women’s status. Atoh has also suggested a connection between rising non-marriage and shifting gender role attitudes (阿藤 1997). In Japan, public discourse has featured two competing narratives regarding women’s social advancement and its relationship to non-marriage and declining fertility. One argument holds that women's participation in the workforce has caused these demographic shifts, while another contends that promoting gender equality and supporting women’s careers is actually the key to reversing fertility decline. These two opposing views continue to coexist in Japanese society. We will examine this issue in more detail in the next installment (Part 2).

Cited literature/Main references

• 赤川学, 2004,『子どもが減って何が悪いか！』筑摩書房．
• 阿藤誠, 1997,「日本の超少出産化現象と価値観変動仮説」『人口問題研究』53(1)：3-20.
• 廣嶋清志, 2000, 「近年の合計特殊出生率低下の要因分解：夫婦出生率は寄与していないか？」『人口学研究』26:1-20.
• 岩澤美帆, 2002,「近年の期間TFR変動における結婚行動および夫婦の出生行動の変化の寄与について」『人口問題研究』58(3)：15-44.
• ———— , 2008,「初婚・離婚の動向と出生率への影響」『人口問題研究』64(4)：19-34.
• ———— , 2015,「少子化をもたらした未婚化および夫婦の変化」高橋重郷・大淵寛編著『人口現象と少子化対策』原書房：49-72.
• James M. Raymo, 2022, The second demographic transition in Japan: a review of the evidence, China Population and Development Studies, 6: 267-287.
• 河野稠果, 2007,『人口学への招待：少子化・高齢化はどこまで解明されたか』中央公論新社.
• 厚生労働省, 2024,「厚生労働白書」
• ———— , 2025,「令和6年人口動態月報年計（概数）の概況」
• 見田宗介ほか編, 2012,『現代社会学事典』弘文堂.
• 日本社会学会編, 2023,『家族社会学事典』丸善出版．
• Robert D. Retherford, Naohiro Ogawa, Satomi Sakamoto, 1996, Values and Fertility Change in Japan, Population Studies, 50(1): 5-25．
• Ron Lesthaeghe, Johan Surkyn, 1988, Cultural Dynamics and Economic Theories of Fertility Change, Population and Development Review,14(1): 1-45.
• 総務省統計局, 2021,「令和2年国勢調査：人口等基本集計結果」
• 筒井淳也, 2023,『未婚と少子化: この国で子どもを産みにくい理由』PHP研究所.
• 山田昌弘, 1999, 『パラサイト・シングルの時代』筑摩書房.
• ———— , 2007,『少子社会日本：もうひとつの格差のゆくえ』岩波書店.

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