Most people consider whether or not to have kids based on lifestyle factors such as , finances, and leisure time, but there’s another group of folks who are doing so primarily for environmental reasons.

This past summer, Time Magazine published a cover story about the childfree life that discussed why people decide to not have kids. Author Lauren Sandler wrote that the birthrate in the US is the lowest in recorded history and that the fertility rate actually dropped by 9 percent between 2007 and 2011. She cites cost ($234,900 to raise a child born in 2011 for a family earning less than $100,000 per year) as a major factor in this decline. Careers are also impacted, especially for women, who may lose out on as much as a million dollars because of lost promotions and other missed opportunities in the workplace that result from taking time off to raise kids.

Sandler also points to the sense of freedom that comes from being childfree. Childfree adults have an abundance of time to spend with friends and family, at their jobs, and on their own leisure activities and self-care.

But there’s a third factor that Sandler neglected to discuss in her popular article—the green angle. Lisa Hymas, writer for Grist.org, wrote about this in a follow-up to the Time story. Hymas points out that the global population is now at 7.1 billion and is projected to reach 9.6 billion by 2050. That’s a lot of people stressing an already exhausted earth. She cites a Global Environmental Change study that boldly discusses the impact of each child on the earth.

The bottom line from this research is that all of the environmentally conscious deeds a person may do -- recycling, riding the bus, etc. -- pale in comparison to not having a child. As Hymas states, “The climate impact of having one fewer child in America is almost 20 times greater than the impact of adopting a series of eco-friendly practices for your entire lifetime.”

Hymas is in the lead in her willingness to boldly address this controversial issue and to encourage potential parents to consider the future of the earth when contemplating their own future. Bringing these issues to the forefront may lead them to forego having a child or to adopt instead.

Would you choose to not have kids primarily for the good of ? And if you wanted to be a parent, would you choose for this same reason?