Statisticians at Oregon State University (OSU) in the US, after a comprehensive study, have determined that family planning is important to reduce the "carbon footprint" of people.
According to the study, some people who are serious about wanting to reduce their "carbon footprint" on the Earth have one choice available to them that may yield a large long-term benefit - have one less child.
In the US, the carbon legacy and greenhouse gas impact of an extra child is almost 20 times more important than some of the other environmentally sensitive practices people might employ their entire lives - things like driving a high mileage car, recycling, or using energy-efficient appliances and light bulbs.
The research also makes it clear that potential carbon impacts vary dramatically across countries.
The average long-term carbon impact of a child born in the US - along with all of its descendants - is more than 160 times the impact of a child born in Bangladesh.
"In discussions about climate change, we tend to focus on the carbon emissions of an individual over his or her lifetime," said Paul Murtaugh, an OSU professor of statistics.
"Those are important issues and it's essential that they should be considered. But, an added challenge facing us is continuing population growth and increasing global consumption of resources," he added.
In this debate, very little attention has been given to the overwhelming importance of reproductive choice, according to Murtaugh.
When an individual produces a child - and that child potentially produces more descendants in the future - the effect on the environment can be many times the impact produced by a person during their lifetime.
Under current conditions in the US, for instance, each child ultimately adds about 9,441 metric tons of carbon dioxide to the carbon legacy of an average parent - about 5.7 times the lifetime emissions for which, on average, a person is responsible.
The researchers make it clear they are not advocating government controls or intervention on population issues, but say they simply want to make people aware of the environmental consequences of their reproductive choices.
"Many people are unaware of the power of exponential population growth," Murtaugh said.
"Future growth amplifies the consequences of people's reproductive choices today, the same way that compound interest amplifies a bank balance," he added.