Your mama may have told you not to put money in your mouth, and she was right on the money.

Researchers at New York University tested dollar bills and found hundreds of different kinds of bacteria, reports the Wall Street Journal. Seriously, their findings will make you want to put on rubber gloves before touching paper cash.

“The NYU researchers identified 3,000 types of bacteria in all — many times more than in previous studies that examined samples under a microscope,” wrote WSJ’s Robert Lee Hotz.

According to the report, Jane Carlton, director of genome sequencing at NYU’s Center for Genomics and Systems Biology, said: “It was quite amazing to us. We actually found that microbes grow on money.”

They found bacteria that cause gastric ulcers, pneumonia, food poisoning, staph infections and genes responsible for antibiotic resistance.

“Their unpublished research offers a glimpse into the international problem of dirty money,” wrote Hotz. “From rupees to euros, paper money is one of the most frequently passed items in the world. Hygienists have long worried that it could become a source of contagion.”

Here’s an upside to the studies on dirty dollars. The NYU researchers most often found a bacterium that causes acne. So, for those of us always fending off requests for money from our teens, we can now say with authority, “No, honey, I can’t give you any money because it will break you out.”

Live Online Chat

Join me at noon ET for my regular online discussion about money. My guest will be Tim Prosch, author of “The Other Talk: A Guide to Talking With Your Adult Children About the Rest of Your Life.” Prosch’s book is the Color of Money Book Club selection for April.

The Pew Research Center found that 47 percent of adults say it is likely that they will be responsible for caring for an aging parent or another elderly family member. Many books on the subject focus on what adult children can do to handle the situation. But Prosch wants you to be proactive about talking with your adult children while you are still physically and mentally able to lead the conversation.

“There is another equally critical time in your kids’ lives when you need to sit them down to talk about the facts of life — discomfort notwithstanding,” Prosch writes. “This time, it’s not about the beginning of life or how babies are made. It’s about the end of life — yours — and the many issues and decisions that will confront you and your children.”

Read more of my review of the book here. And here’s the link to join the online chat today or post a question.

Banking on Their Home

Is your home your retirement plan?

If so, you may find yourself short of the money you need to retire comfortably.

Americans are more likely to think real estate is the best option for long-term investments ranking ahead of stocks and gold, according to a recent Gallup poll.

“The fact that Americans still financially fetishize homeownership baffles me,” wrote Catherine Rampell, an opinion columnist at The Washington Post. “Never mind that so many people lost their shirts (among other possessions) in the recent housing bust. Over an even longer horizon, owning a home has not proved to be a terribly lucrative investment either.”

Rampell says don’t believe her. Just follow the math.

“Over the past century, housing prices have grown at a compound annual rate of just 0.3 percent once one adjusts for inflation, according to my calculations using Shiller’s historical housing data,” she reports. “Over the same period, the Standard & Poor’s 500-stock index has had comparable annual returns of about 6.5 percent. Yet Americans still think it’s financially savvy to dump all their savings into a single, large, highly illiquid asset.

Color of Money Question of the Week

Is home ownership still worth it? Send your comments to colorofmoney@washpost.com. Please include your full name and city. I don’t like to post anonymous comments.

April is Financial Literacy Month

So, have you done something this month to increase your financial literacy?

What people don’t know about their personal finances is costing them big time. For last week’s question I asked: What do you think of the state of financial education in the U.S.?

Here’s what some of you had to say:

“Focusing on the reason why people don’t bother to budget is more important than trying to assess how many people understand the intricacies of establishing a budget,” wrote Robbie Steinmetz of Tulsa, Okla.

If we want adults to be financially literate, we should start in middle school, wrote Ted Korolewski of Wild Rose, Wis. “Poor financial management decisions cause lifelong problems,” he wrote. So, beginning in middle school, students should be required to take money management classes, he said, and the classes should get harder as students advance.

Carrol from Laurel, Md., agreed: “As important as financial education is and how detrimental the lack thereof continues to be on virtually everyone in our country, you would think there would be a series of required financial literacy lessons that are provided at every educational level starting in elementary school and continued in both middle and high school.”

Many of those who responded said they understood why so many people have trouble with this financial stuff.

“I think people procrastinate on personal finance because they are scared of seeing the actual numbers and understanding what their current financial situation means, so they just avoid and the situation gets worse,” wrote Monica from Washington, D.C., who started the Frugal Optimist blog about her and her husband’s efforts to get out of debt. “I think financial education is a never-ending class we all take, and the best thing we can do for ourselves is to research the heck out of any financial topics — Mortgages, College Saving Funds, Retirement, or Refinancing — before making any decisions! The information is there. You just have to be willing to take the time to look at multiple sources.”

Well put, Monica.

Fearless Financial Ideas

On May 1, come learn how to spend well and live rich when I give a talk as part of the University of Maryland Alumni Association’s Fearless Event Series.

As an alum, I’ll be speaking and sharing practical advice to help you start living your best financial life. Your financial life doesn’t have to be a game of chance.

The event is being held from 6 to 9 p.m. at VisArts, 155 Gibbs St., Rockville. For more information and to register, click here.

Readers may write to Michelle Singletary at The Washington Post, 1150 15th St. NW, Washington, D.C., 20071, or michelle.singletary@washpost.com. Personal responses may not be possible, and comments or questions may be used in a future column, with the writer’s name, unless otherwise requested. To read previous Color of Money columns, go to www.postbusiness.com. Follow Michelle on Twitter.