In May, National Geographic landed in my mailbox with a cover of an infant and the headline, “This baby will live to be 120.” The article inside described the type of medical and scientific advances that will slow the aging process and add years to the average length of life — gradually as it has for decades, but, at a certain point, with a giant leap forward.

My first thought: “Wow, lucky kid.” My second thought: “Would I really want to live that long?” Turns out, a lot of Americans would not.

Asked if they would choose to undergo medical treatments to slow the aging process and live to be 120 or more, 56 percent of respondents in a Pew Research Center survey released earlier this month said they’d decline. The reasons vary, ranging from the strain such long lifespans would put on society, including, presumably, the U.S. health care system, to the pressure on their own finances, to the belief that those medical advances “interfere with the natural cycle of life.”

At the same time, 54 percent of adults believe “medical treatments these days are worth the costs because they allow people to live longer and have better-quality lives.” However, while 79 percent of respondents say the extreme life-lengthening treatments should be available to everyone, two-thirds think that only wealthy people will have access to them.

The survey was conducted this spring among a nationally representative sample of 2,012 adults across all 50 states.

So how long would Americans choose to live? Sixty-nine percent said 79 to 100 years, with the median falling at 90 years, which, as the Pew researchers noted, is about 11 years longer than the current average U.S. life expectancy of 78.7 years.

It will be interesting to see how many of those respondents feel nine decades on this earth is long enough if and when they hit 89. Would you?