Cassie King grew up in San Diego, the daughter of loving parents, and she’d wanted to be a teacher since she was 5 years old. As a teenager, she had planned to have children of her own. 

“But with more health crises and climate catastrophes, I started to worry more about the state of the world in just 10 years, let alone in 100 years when the children of my grandchildren would be having kids,” she said. “That makes me feel like it would be wrong to bring someone into that chaos, without their consent.”

After graduating college at the University of California, Berkeley in 2018, she is now working full-time as an animal rights activist, and she has decided never to give birth. 

King, 23, is emblematic of a growing number of young people who are worried about having children in a world marked by climate and ecological crises and threatened by overpopulation.

Two nonprofits, Fair Start Movement and Population Balance, filed a complaint in late October with the United Nations Human Rights Council, on behalf of King and other young women, alleging that the United Nations has failed to protect the rights of younger generations to safely and sustainably have children.

“Young people are increasingly choosing not to have children, not because they don’t want them, but because they’re worried about how the climate crisis will impact their children’s future,” said Carter Dillard, policy advisor for Fair Start, which advocates on behalf of families and children and is based in San Francisco. 

The United Nations is obligated to interpret the “right to found a family” from Article 16 of the Universal Declaration of Human Rights in a way that preserves that right for generations to come, Dillard said. Instead, U.N. member states have limited the ability of future generations to found a family in a safe and healthy way by “encouraging unsustainable population growth models that have contributed to climate change.”

The obligation to protect the right of future generations to found a family flows from the Council’s vote a month ago, adopting a resolution formally recognizing a healthy and sustainable environment as a basic human right, the complaint alleges. 

Eleven percent of childless adults cite climate change as a “major reason” for why they do not currently have children, and another 15 percent say it’s a “minor reason,” according to a nationally representative 2020 survey by Morning Consult, a data and polling company. 

While climate change was less cited in the survey than other reasons for not having children, like financial issues and career aspirations, the responses suggested that climate change is a growing concern for a younger generation of Gen Z-ers born between 1997 and 2012.

According to their website, the Fair Start Movement was founded in 2014, in the belief that ensuring children “a fair start in life” means providing incentives for smaller and well-planned families, which will also serve as a pathway to a more sustainable future. 

Population Balance, based in Minneapolis, wants to achieve a smaller human footprint by challenging overconsumption and pronatalism, the policy and practice of encouraging people to have children. 

Both groups would like to see the social bias and pressure shift away from reproduction toward having fewer children or no children at all. But some experts worry about the stigma that a change in cultural norms might place on poor and minority women.

“While wealthy white women are generally applauded and congratulated when they reproduce, poor and minority women are already stigmatized for reproducing,” said Quill R. Kukla, a philosophy professor at Georgetown University. “Those women will face disproportionate judgment if we entrench the idea that reproduction is selfish or socially undesirable.” 

Under the U.N. Human Rights Council’s formal complaint procedure, working groups will first assess complaints that are filed and bring those that demonstrate “consistent patterns of gross and reliably attested” human rights violations to the attention of the Human Rights Council. 

Dillard hopes that the Council will ultimately decide to take the matter up for public consideration, which may lead to a formal resolution process. Resolutions are voted on by member states and represent the position of the majority of the Council’s members on an issue. They can request investigations, call for public debate and develop recommendations and standards.

While the Council’s actions, including resolutions, are not legally binding, its decisions carry political weight and influence the behavior and global perception of nations. Since it was established in 2006, the U.N. Human Rights Council has been regarded as the world’s foremost human rights body, although a number of its 47 members are some of the most egregious rights abusers. 

For Cassie King, the question surrounding procreation in the age of climate change is two-fold: she is worried about bringing children into a world that’s expected to face higher temperatures, more extreme weather events and poorer air and water quality. And she’s worried about the impact that having children could have on global warming. 

A 2017 study published in Environmental Research Letters recommended having one fewer child as the most effective personal lifestyle choice that would reduce greenhouse gas emissions in developed countries. According to the study, one U.S. family who chooses to have one fewer child would provide the same level of emissions reductions as 684 teenagers choosing to recycle comprehensively for the rest of their lives.

Some people in the public sphere have broached the issue. Rep. Alexandria Ocasio-Cortez (D-N.Y.) said in an Instagram live stream in March of 2019 that it’s a “legitimate question” to wonder if it’s still OK to have children given that “there’s a scientific consensus that the lives of children are going to be very difficult. Later that year, Prince Harry said in an interview with British Vogue that he and his wife, Meghan Markle, would have no more than two children to limit their environmental impact. 

But concerns about climate change and its impact on child-bearing people and their children aren’t just worries for the future. There is a growing body of evidence that links high temperatures and pollution to worse birth outcomes, such as stillbirth, preterm birth and babies born with low birth weight. 

“If they make it, they don’t always have an easy life—they have an elevated risk of respiratory and neurologic problems in the first few years of their life, and are more likely to get major serious illnesses in adult life,” said Bruce Bekkar, a retired obstetrician-gynecologist who now serves on the board of the advocacy group Climate Action Campaign. 

Bekkar co-authored a 2020 report in the Journal of the American Medical Association that looked at 57 studies published since 2007 that examined heat and air pollution exposure’s effect on newborn children. The study found that the toll of environmental harm is felt disproportionately by Black mothers and babies. 

“Many of the factors unfortunately tend to reinforce one another and occur simultaneously for certain groups,” Bekkar said. 

For example, people who are living in urban heat islands are also living near busy freeways and other polluting sources from industrial sites, Bekkar said. A lot of times, they are also far from markets that sell fresh produce, and they can’t afford reliable access to health care. 

Despite these harms, “we tolerate governments pushing women to have lots of kids and the unsustainable population growth it causes,” the complaint alleges. Governments do so by “actively preventing” access to family planning education, contraception and abortion services.

“The best interpretation of the right to have children would have required the redistribution of wealth to women and children in the mid-20th century,” Dillard said. “Instead it went to the top of the wealth pyramid. We are trying to reverse that.”