Father and son shared little in common. There were no Little League games, no backpacking trips, no going to the movies together. The father, Raymond Marquez, was just too busy.

From the 1950s into the 1990s, the elder Marquez, now 78, was spending most of his time at his gambling parlors in Harlem, building a reputation as Spanish Raymond — the notorious kingpin of the illicit numbers racket. Mr. Marquez became known for flashy clothes and jewelry, owning luxury cars and even a yacht.

His son, Raymond David Marquez — he goes by R. David Marquez — was on a much different track. He went to elementary school in Great Neck, N.Y., an affluent community on Long Island where he grew up, bounced around boarding schools and then went to college. Of his father's business, he said: ''It really didn't faze me one way or the other. I always stayed in school. I was trying to become somebody, trying to do something.''

Despite their differences, this father-son tandem is now linked in a way few others are: The son is his father's lawyer.

After a decade-long focus on civil cases involving medical malpractice and personal injury, David, in 1994, began devoting a large part of his practice, which he runs out of the family home in Great Neck, to his father, representing him in both criminal and civil matters.

David, 57, helped negotiate a plea agreement for his father in a 1994 gambling case in Manhattan. He has defended his father against attempts by the city and state to collect back taxes and won his father an acquittal on gambling charges filed in 1998 by the Manhattan district attorney. Most recently, he represented his father in a $15 million lawsuit against the city that claimed that his father had gotten bladder cancer from secondhand smoke while in detention at Rikers Island. A jury this month found the city not responsible.

Still, Raymond Marquez has not avoided serious legal problems. He served eight years in a federal prison, has had to forfeit $1 million in assets, served five years of probation and still owes the city more than $1 million in back taxes.

He said he encouraged his son as a child to pursue the law because he spent a lot of time around lawyers — socially and as a client — and liked the work they did. ''He works very hard at whatever he does,'' Mr. Marquez said. ''He's very thorough.''

David is not surprised by his father's sentiment. ''He was trying to elevate the family'' by running numbers, he said. ''He wasn't trying to create a crime dynasty.''

Bonded by kinship and court appearances, the two men have a somewhat ambivalent relationship.

On the one hand, because lawyers must have a good rapport with their clients — having to tell them hard truths they might not want to hear — Raymond and David Marquez are close on some level. Yet people involved in cases with them said their relationship seems very businesslike.

David Marquez said he represents his father with no more vigor than he does any of his other clients. He took on the smoking case, he said, because he believed that the city did was in the wrong, not simply because his father said he was a victim.

Raymond Marquez was born and raised in Harlem, the son of natives of Puerto Rico who eked out a living running a grocery store in Harlem. He graduated in 1947 from Textile High School on 19th Street in Manhattan, where he met his wife, Alice, who was born in the Bronx and is also of Puerto Rican descent.

David Marquez, who was born in 1951, lived with his parents in a small one-bedroom apartment on 95th Street between Broadway and Amsterdam Avenue. He was their only child. When he was about 3, his father bought a home in Great Neck.

Raymond said his mother bought the ranch-style house for him in 1953 for about $30,000. He said he later repaid his mother. With its finely manicured lawns and statuettes decorating the inside and outside, it is a leap up from the drab parlors where the numbers business boomed.

In Great Neck, David Marquez said, he stood out as a Puerto Rican among mostly white neighbors. Trying to find a place where he fit in, he attended boarding schools in Tarrytown, N.Y., Cornwall-on-Hudson, N.Y., and Bristol, Conn. He eventually returned to Great Neck for his senior year and graduated from public high school there.

In school, David Marquez said, he did not know exactly what his father was doing, only that he was different from the other fathers. His father spent days away from home, and he would see him mostly on weekends. His father took him to Harlem every now and then to see his grandparents. But he said he never took him to a gambling parlor.

As he got older, David picked up tidbits of his father's life here and there — in newspaper articles, conversations with family members and with school friends whose parents, he said, were also involved in crime.

In 1969, Raymond went to prison on federal gambling charges. While his father was behind bars, David got a bachelor's degree from Inter-American University of Puerto Rico in business and economics, an M.B.A. from Adelphi University in Garden City, N.Y., and a law degree from Inter-American.

Though he was not bitter with his father, David said, visiting him in prison was difficult.

''I was never mad at him for what he did,'' he said. ''I always understood that we were living the benefits of his activities. I wasn't raised poor.''

But Raymond, who said he never wanted his son to have any part in his criminal business, was not proud of the example he set. ''I'm sure he's not too happy with the life I've lived,'' he said. ''I'm unhappy that I couldn't offer him a better social presentation, that I couldn't be in a category that's more socially accepted.''

David, who has been practicing law in New York since 1984, said he believed some judges may have been hard on him because of his father's past. And his relationship with some fellow lawyers soured after they found out who his father was, he said. ''I do believe that the association between my father and I, despite our differences in careers, that it's had a negative impact on my career,'' he said.

Still, people who have seen David in the courtroom described him as polite, passionate in his arguments and sometimes awkward with his humor. ''He is one of the hardest-working, hardest-fighting lawyers for the rights of his clients who I've seen over the years,'' said Stuart Perry, a lawyer who has worked with David.

Despite illnesses including bladder cancer, arthritis and macular degeneration, Raymond can show a fire similar to his son's. His ailments have taken their toll. He said he tires easily and is usually in bed by 7 p.m. He is eager to talk about his past.

He remains adamant that law enforcement authorities unfairly made him a target. He said that he was a hard worker like anyone else and that he was living a middle-class life, not the life of a millionaire. Mr. Marquez blamed Robert M. Morgenthau, the Manhattan district attorney, for his troubles.

Mr. Morgenthau prosecuted him on federal gambling charges when he was a United States attorney in the 1960s, and since he has been the Manhattan district attorney, his office has prosecuted him twice. Mr. Marquez reached a plea agreement on gambling charges in 1996, and was acquitted of gambling charges in 2001.

''I sometimes question myself, 'Why this fanatical pursuit of me by a man like Robert Morgenthau?' '' Mr. Marquez said. ''It's just something that I cannot understand.''

Mr. Morgenthau declined to comment, but Daniel J. Castleman, the chief assistant district attorney, said that the evidence against Mr. Marquez had been compelling and there was little question about his stature in the numbers business.  

''This was not some small fish,'' Mr. Castleman said. ''He was the biggest thing in numbers for three decades or more.''

Raymond Marquez now divides his time between Fort Lauderdale, Fla., where his wife owns a hotel and a motel, and Great Neck, where David lives in the house that was bought in 1953. He said he occasionally buys a lottery ticket, but has not participated in the numbers racket in a decade, not because he opposes it, but because he was so far removed from that environment.

Their legal partnership could soon come to an end. David is considering appealing the decision in the smoking case, the last of the cases in which he is representing his father. Once they leave the courtroom for the last time as client and lawyer, their relationship may no longer have a strong anchor.

Raymond and David speak regularly and get along well, but they acknowledged that their differences might prevent them from sharing a truly intimate bond.

''If I were a lawyer and he was a lawyer, we'd have something in common,'' Raymond Marquez said. ''Or if we were both in the numbers game, we'd have those in common. But we're on opposite sides of the fence with a big gap in between. That gap does create a problem in that we don't see eye to eye and we can't.''

David Marquez interjected: ''Does that mean that when it comes to legal battles that I would turn my back on him? No.''

Copyright 2008 The New York Times Company