Martin Kolk
@martinkolk.bsky.social
Demographer at Stockholm University and the Institute for Future Studies.
https://www.su.se/profiles/mkolk
https://www.su.se/profiles/mkolk
People with greater climate worry and propensity for climate action are more likely to be worried about the future of a child living in a deteriorating world, than that an additional child may contribute negatively towards such a future. We find weak correlations with political attitudes and trust.
August 19, 2025 at 12:45 PM
People with greater climate worry and propensity for climate action are more likely to be worried about the future of a child living in a deteriorating world, than that an additional child may contribute negatively towards such a future. We find weak correlations with political attitudes and trust.
Different eco-reproductive concerns are moderately correlated with each other, and relatively weakly correlated with whether people have children or not. We find that the same people largely support policies reducing population both in their own country, and in developing countries.
August 19, 2025 at 12:45 PM
Different eco-reproductive concerns are moderately correlated with each other, and relatively weakly correlated with whether people have children or not. We find that the same people largely support policies reducing population both in their own country, and in developing countries.
In a second study, with over 600 participants, we asked how much environmental factors should influence childbearing decisions - both the possible impact of a worsening environment on the child, and that an additional child may contribute to an increasing population that may worsen the environment.
August 19, 2025 at 12:45 PM
In a second study, with over 600 participants, we asked how much environmental factors should influence childbearing decisions - both the possible impact of a worsening environment on the child, and that an additional child may contribute to an increasing population that may worsen the environment.
We find that younger people and women are more worried about climate change, while men are more concerned about overpopulation. Parents with more children tend to be more concerned about future generations but less worried about overpopulation.
August 19, 2025 at 12:45 PM
We find that younger people and women are more worried about climate change, while men are more concerned about overpopulation. Parents with more children tend to be more concerned about future generations but less worried about overpopulation.
Our first data set is 8,000 respondents in the Swedish Gender and Generation Survey. Respondents were asked about worries such as climate change, overpopulation, and the prospects of future generations. Worries about three things are widespread.
August 19, 2025 at 12:45 PM
Our first data set is 8,000 respondents in the Swedish Gender and Generation Survey. Respondents were asked about worries such as climate change, overpopulation, and the prospects of future generations. Worries about three things are widespread.
In our new study in Population and Environment, we examine how environmental concerns shape public attitudes toward childbearing in Sweden. We find views linking environmental concerns with reproduction are widespread, even if we find less support that they affect behavior.
doi.org/10.1007/s111...
doi.org/10.1007/s111...
August 19, 2025 at 12:45 PM
In our new study in Population and Environment, we examine how environmental concerns shape public attitudes toward childbearing in Sweden. We find views linking environmental concerns with reproduction are widespread, even if we find less support that they affect behavior.
doi.org/10.1007/s111...
doi.org/10.1007/s111...
Much of the increasing gender gap is compositional, with increasing shares of migrants with larger gender gaps, increasing the employment gap in the population.
Among Swedish men and women, employment has decreased, but much less.
Different time series 2005-2024 (with different age categories)
Among Swedish men and women, employment has decreased, but much less.
Different time series 2005-2024 (with different age categories)
August 11, 2025 at 4:34 PM
Much of the increasing gender gap is compositional, with increasing shares of migrants with larger gender gaps, increasing the employment gap in the population.
Among Swedish men and women, employment has decreased, but much less.
Different time series 2005-2024 (with different age categories)
Among Swedish men and women, employment has decreased, but much less.
Different time series 2005-2024 (with different age categories)
And here is the same figure for age 16-64. Essentially the same pattern, though more dramatic decline in employment (due to more enrolled students at younger ages).
August 11, 2025 at 4:17 PM
And here is the same figure for age 16-64. Essentially the same pattern, though more dramatic decline in employment (due to more enrolled students at younger ages).
Sweden reached near gender parity in employment in the late 1980s, and if anything, the gender gap has increased since then.
There used to be near-universal employment among Swedish men, with Swedish women nearly catching up in the 1980s.
Swedish labor force survey, age 35-44.
There used to be near-universal employment among Swedish men, with Swedish women nearly catching up in the 1980s.
Swedish labor force survey, age 35-44.
August 11, 2025 at 4:17 PM
Sweden reached near gender parity in employment in the late 1980s, and if anything, the gender gap has increased since then.
There used to be near-universal employment among Swedish men, with Swedish women nearly catching up in the 1980s.
Swedish labor force survey, age 35-44.
There used to be near-universal employment among Swedish men, with Swedish women nearly catching up in the 1980s.
Swedish labor force survey, age 35-44.
However, women are not consistently more endogamous, nor are they always less likely to switch. Patterns depend on the strictness and size of the denomination.
July 16, 2025 at 1:28 PM
However, women are not consistently more endogamous, nor are they always less likely to switch. Patterns depend on the strictness and size of the denomination.
Gender matters, but not uniformly. In endogamous unions created by conversion, wives more often adopt the husband’s faith — especially in Islam and Judaism. For Lutherans, it is husbands who usually join the wife’s religion.
July 16, 2025 at 1:28 PM
Gender matters, but not uniformly. In endogamous unions created by conversion, wives more often adopt the husband’s faith — especially in Islam and Judaism. For Lutherans, it is husbands who usually join the wife’s religion.
When do switches happen? For every group except Lutherans, conversions spike in the two year band around the wedding, driving sharp jumps in homogamy. Among Lutherans, secularisation means conversions reduce endogamy over the life course.
July 16, 2025 at 1:28 PM
When do switches happen? For every group except Lutherans, conversions spike in the two year band around the wedding, driving sharp jumps in homogamy. Among Lutherans, secularisation means conversions reduce endogamy over the life course.
Once we control for group size, odds of marrying inside one’s faith explode for stricter or migrant dense groups: 50 to 1 000 fold higher than random matching for Other Protestants, Other Christians, Islam and Judaism, reflecting strong endogamy.
July 16, 2025 at 1:28 PM
Once we control for group size, odds of marrying inside one’s faith explode for stricter or migrant dense groups: 50 to 1 000 fold higher than random matching for Other Protestants, Other Christians, Islam and Judaism, reflecting strong endogamy.
Endogamy at the wedding is high in the majority church (≈ 81 % of Lutherans marry another Lutheran) but far lower for minority groups (≈ 40 % among the unaffiliated, ≈ 15 % among Orthodox).
However, this is largely due to the relative size of the different groups.
However, this is largely due to the relative size of the different groups.
July 16, 2025 at 1:28 PM
Endogamy at the wedding is high in the majority church (≈ 81 % of Lutherans marry another Lutheran) but far lower for minority groups (≈ 40 % among the unaffiliated, ≈ 15 % among Orthodox).
However, this is largely due to the relative size of the different groups.
However, this is largely due to the relative size of the different groups.
We have annual denomination records linked to marital histories. We observe each spouse’s religion at age 17, the wedding year, and every year to age 45. That lets us see when, not just whether, someone switched faith.
July 16, 2025 at 1:28 PM
We have annual denomination records linked to marital histories. We observe each spouse’s religion at age 17, the wedding year, and every year to age 45. That lets us see when, not just whether, someone switched faith.
Our unique data includes, population level registers, 1.16 million spouses, religious denominations organized in nine faith categories.
Finland maintains a national longitudinal register on religious affiliation.
Finland maintains a national longitudinal register on religious affiliation.
July 16, 2025 at 1:28 PM
Our unique data includes, population level registers, 1.16 million spouses, religious denominations organized in nine faith categories.
Finland maintains a national longitudinal register on religious affiliation.
Finland maintains a national longitudinal register on religious affiliation.
In a new preprint by Linus Andersson, myself and Jan Saarela, we tracks every marriage in Finland 1972 2020 to show how religious conversions shape endogamy — and how those patterns differ for men and women.
doi.org/10.17045/sth...
doi.org/10.17045/sth...
July 16, 2025 at 1:28 PM
In a new preprint by Linus Andersson, myself and Jan Saarela, we tracks every marriage in Finland 1972 2020 to show how religious conversions shape endogamy — and how those patterns differ for men and women.
doi.org/10.17045/sth...
doi.org/10.17045/sth...
If anyone wants to learn more about households and kinship in Sweden, they can join this seminar at 13:00 CET where I present a new study on how an indivudal's household members change over the life course.
www.su.se/department-o...
www.su.se/department-o...
March 26, 2025 at 11:51 PM
If anyone wants to learn more about households and kinship in Sweden, they can join this seminar at 13:00 CET where I present a new study on how an indivudal's household members change over the life course.
www.su.se/department-o...
www.su.se/department-o...
Transgender men and women have substantially lower socioeconomic outcomes than cisgender men and women, regardless of the age at which they transition or the historical period. This is measured at the year of our observed transition event.
March 17, 2025 at 1:10 PM
Transgender men and women have substantially lower socioeconomic outcomes than cisgender men and women, regardless of the age at which they transition or the historical period. This is measured at the year of our observed transition event.
We also examine prevalence at the cohort level and find less variation across cohorts, though still a clear increase for cohorts born in the mid-1990s and onwards. We find that gender transitions (defined by the events we observe in our data material) take place at younger ages than in the past.
March 17, 2025 at 1:10 PM
We also examine prevalence at the cohort level and find less variation across cohorts, though still a clear increase for cohorts born in the mid-1990s and onwards. We find that gender transitions (defined by the events we observe in our data material) take place at younger ages than in the past.
The recent increase in transition prevalence is most pronounced among people in early adulthood; in particular, young transgender men drive an increase in overall transition rates through 2018, followed by moderate declines in 2019 and 2020.
March 17, 2025 at 1:10 PM
The recent increase in transition prevalence is most pronounced among people in early adulthood; in particular, young transgender men drive an increase in overall transition rates through 2018, followed by moderate declines in 2019 and 2020.
The measured prevalence rates of diagnoses and legal gender changes are low in all periods, although they have increased since the early 2010s. By 2020, only 0.07% of the Swedish population had received a gender incongruence diagnosis and only 0.03% had changed legal gender.
March 17, 2025 at 1:10 PM
The measured prevalence rates of diagnoses and legal gender changes are low in all periods, although they have increased since the early 2010s. By 2020, only 0.07% of the Swedish population had received a gender incongruence diagnosis and only 0.03% had changed legal gender.
In a new study recently published in Demography, Kolk, @jlucastilley.bsky.social, @ylvamoberg.bsky.social , von Essen, and Burn provide a detailed sociodemographic overview of the Swedish transgender population.
doi.org/10.1215/0070...
(@readdemography.bsky.social)
doi.org/10.1215/0070...
(@readdemography.bsky.social)
March 17, 2025 at 1:10 PM
In a new study recently published in Demography, Kolk, @jlucastilley.bsky.social, @ylvamoberg.bsky.social , von Essen, and Burn provide a detailed sociodemographic overview of the Swedish transgender population.
doi.org/10.1215/0070...
(@readdemography.bsky.social)
doi.org/10.1215/0070...
(@readdemography.bsky.social)
In practice, those aged 77+ live on pensions and receive extensive public care, so upward transfers are very substantial (paid by pay-as-you go taxes by working ages, at least in Sweden), and older cohorts consume much more when you combine public and private goods than working-age individuals.
February 25, 2025 at 10:52 PM
In practice, those aged 77+ live on pensions and receive extensive public care, so upward transfers are very substantial (paid by pay-as-you go taxes by working ages, at least in Sweden), and older cohorts consume much more when you combine public and private goods than working-age individuals.
Compared to all previous societies in human history, financial transfers in old age have reversed in contemporary European welfare states such as Sweden.
Virtually none among the oldest (here aged 77+) receive transfers from their children, while it is very common to give downward transfers.
Virtually none among the oldest (here aged 77+) receive transfers from their children, while it is very common to give downward transfers.
February 25, 2025 at 10:52 PM
Compared to all previous societies in human history, financial transfers in old age have reversed in contemporary European welfare states such as Sweden.
Virtually none among the oldest (here aged 77+) receive transfers from their children, while it is very common to give downward transfers.
Virtually none among the oldest (here aged 77+) receive transfers from their children, while it is very common to give downward transfers.