Twin sisters Elaine Foster and Evelyn Lowe joined the centenarian club in March, celebrating their 100th year of life surrounded by family in Bowie, Maryland.

When asked by TODAY as to what they credit with their longevity, neither could give an answer.

“I haven’t the slightest idea,” Foster said. “I don’t know how I happened to live as long as I have,” with sister Evelyn agreeing ““I have not the vaguest idea.”

The sisters live together and largely take care of themselves. Lowe’s great-grandson, Darvell Green, lives with them and helps them out when needed, such as grocery shopping and cooking, and dolling out their daily medications.

But other than that, the sisters live their own lives and do what they want, including regular spa days.

Scientists who have studied longevity say there is a particular combination of genes that are the secret to living an extraordinarily long life.

“It’s the right combination of genes that makes these individuals rare. So it’s not one rare gene, it’s getting the variants of 130 or so genes just right. It’s like winning the lottery,” said Dr. Thomas Perls, professor of medicine and geriatrics at Boston Medical Center, and director of the New England Centenarian Study.

Surprisingly, the only ailment the sisters suffer from is arthritis, and they walk on their own but do have canes to help maintain their balance. “I do go once a year to get a checkup” Foster said. “I think everybody should.”

In addition to enjoying bacon and eggs every morning, Elaine Foster also has a glass of wine every evening. Both sisters were smokers in their younger years but eventually quit.

The family is hopeful that they will have the spunky sisters with them for several more years to come.

“If I live to be 100, I’d love to be in their state,” Green, 27, said. “I always ask (my great-grandmother) all the time: What do you do to stay so healthy and live so long? She never really goes into detail about anything, but she always says she drinks her wine.”