Having a child is unethical because of the child’s impact on the planet’s health. The world is already full of people. Those people are collectively using too many resources. Adding a new person contributes to this massive problem. The planet cannot sustain a population of more than 7 billion people.
This situation is evident from the drastic effects of climate change today, including rising sea levels, increasing droughts, and destroyed aquatic ecosystems. Population growth affects the Earth’s ability to withstand climate change and absorb emissions, such as through deforestation.
In other words, the climate crisis is a reproductive crisis. This argument receives support from scientific research. A 2017 study has found that the most impactful thing a human could do for the planet was to have one fewer child. Having one child instead of two would save 58 tons of carbon dioxide for each year of the parent’s life. That figure was calculated by combining the emissions of the child and all their descendants, then dividing this total by the parent’s lifespan. Another study from Oregon State University found that each child adds an even 9,441 metric tons of carbon dioxide to the carbon legacy of each parent.
Additionally, other scientific research has shown that slowing population growth could eliminate one-fifth to one-quarter of all the carbon emissions that need to be cut by midcentury to avoid the catastrophic tipping point.
Some philosophers argue that it is morally better to make people happy than to make happy people. Those who exist already have needs and wants. Protecting and providing for them is motivated by respect for human life. It is not a harm to someone not to be created. Since having children threatens the lives of existing people, childbearing is unethical.
Overall, having a child equals contributing to systematic harm that occurs as a result of overpopulation. Therefore, it is not ethical to have a child.