"As you get older and when you have children, you become more and more interested about what's going to happen to you and what you are going to pass on to them," Harriett Levin Balkind told Ivanhoe.

Levin Balkind keeps fit inside and out, but she worries about what she can't control -- Parkinson's, hereditary heart disease and Alzheimer's.

"My husband's father died of Alzheimer's and on my side of the family, my father's sisters both had Alzheimer's," she said.

She and her husband turned to a private company to test their DNA … not only for themselves, but to help predict future health issues of their only son.

"It's such a fascinating way to learn about yourself and we thought why not take this out to individuals, give them an opportunity to learn about their own genetics?" Linda Avey, co-founder of 23andMe in Mountain view, Calif., said.

Avey and Anne Wojcicki are the creators behind 23andMe -- a simple $399 test that was named Time magazine's Invention of the Year.

"It's all in the saliva and it's just a matter of measuring those points in the genome," Avey explained.

The home test takes some spit that's sent off to a lab. Results of more than 100 traits are posted on a password protected website.

"The first thing it told me, which completely blew me away, was you're an Ashkenazi Jew, and that just was amazing to me" Levin Balkind recalled.

Your DNA can be traced back to its roots, showing the journey of your ancestors, tracking each generation. The past is very definitive. The future is not so black and white.

"We're looking at the genetics of more common diseases and they're not so deterministic," Avey said. "You could have an increased risk for something like heart disease or rheumatoid arthritis. That doesn't mean you're going to get the disease."

Critics warn tests like these can be deceiving.

"If you do a DNA test on someone to predict their risk of heart disease, you're really only looking at a part of the picture," Marta Gwinn, M.D., M.P.H., a medical epidemiologist in the National Office of Public Health Genomics at the Centers for Disease Control and Prevention in Atlanta, said. "You're really only looking with what they came with -- the hand they were dealt -- when we know that so much of your future health depends on how that hand is played."

"People might be a little startled at first with the information, but I'd say all in all, for those people who are fearful of getting this information, they're just not signing up to begin with and the people who are signing up are those who say, 'I think information is power,'" Avey said.

"Knowing yourself and knowing how you're going to react to having information is really important and critical for any genetic test," Susannah Baruch, J.D., the law and policy director at Johns Hopkins University's Genetics and Public Policy Center in Washington, D.C., said.

Kaye Neufeld knows she's strong. She's a cancer survivor. Her reason for taking the test?

"Six years ago I was diagnosed with breast cancer and it came to me as a shock because I had done everything right," she explained. "I've been on a mission to find out maybe why this happened."

For Neufeld, 23andMe did not give her the answer she was looking for.

"They did test for three breast cancer genes and I didn't carry any of the risks for that, so I still think there's something else going on with genetics, and I'm still looking for that answer," she said.

But the test did reveal Neufeld has a 55 percent risk for blood clots -- the same condition that killed reporter David Bloom in Iraq.

"Now that I know, I can be proactive and be sure that I get plenty of exercise and move my legs and help to prevent that from happening to me," Neufeld said.

Levin Balkind's husband found out what was causing his lifelong stomach problems.

"The test results show that I am lactose intolerant," Aubrey Balkind explained. "I went to a doctor and they confirmed, yes, I have lactose intolerance."

As for Levin Balkind, Alzheimer's is not part of the 23andMe DNA test yet, but she did learn that she was low risk for Parkinson's and a high risk for diabetes and high blood pressure.

"It makes you realize you have control -- that you have more control than you thought," she said.

Gene experts warn this is a new field. They're learning more about the human genome every day. Results will change and people need to be aware that test results are not written in stone.

"This isn't definitive yet," Avey explained. "We're really on the cutting edge of this, so it has to be taken in the proper light -- that it can change."

"I wouldn't want to be seen as arguing against the research or against the development of useful tests," Dr. Gwinn said. "I just want people to think before they spit and use their money wisely."