NEW YORK -- Tough economic times have increased the number of family-run businesses.

But could you imagine going into business with your brother or sister?

Brothers Alexander and Dimitri Gatanas never thought they would be back in the family's nursery business, in Harlem -- much less running it. But necessity forced their decision to join forces in a sibling enterprise.

"It was because my grandfather passed away and my grandmother needed help running the business," Dimitri Gatanas, of Dimitri's Garden Center, said.

Sisters Kathlin and Megan Argiro had talked for years about teaming up in Kathlin's design business in New York's Garment District. But it was just talk until Megan decided to exit the Washington Beltway and bow out of a political career.

"Your starting point is so much further ahead than you would be with just a business partner,for example. You really know the person and she can tell me what she's thinking without even saving a word," Megan Argirosaid.

The thought of going into a business with a brother or sister may sound very appealing, especially in touch economic times. But it does present some unique challenges in terms of personality politics.

Arthur Levy and his wife, Rosann, who spent years together in a family accounting firm, now run a nonprofit organization to help small businesses survive. They've set up the Small & Family Business Foundation to help other people do the same.

"Set the rules upfront, who's going to do what, how much money you're going to put up, how much equity you're going to put in and who's going to stay out of it."

Both the Argiro sisters and the Gatanas brothers say keeping focused on the common goal helps keep the peace.

"You have to maintain a professional demeanor, you want everyone to feel comfortable, you don't want to get involved in sibling stemmed fights in a work environment, so that is a challenge," Kathlin Argiro said.

"At the end of the day we enjoy going out to dinner after yelling at each other all day, we enjoy each others company, just two brothers hanging out ... he's going to be the best man at my wedding, I can't not like him too much," Dimitri Gatanas said.