A man who gave up custody of his own son amid a sex abuse investigation involving a foster child has been promoted to lead South Florida’s oldest and largest service group for people with the virus that causes AIDS — and their families.

Michael McGuigan is the new CEO of Broward House, founded in 1988, which serves over 6,000 men, women and children with HIV and AIDS at 15 Broward County centers.

Just this past summer, McGuigan, 53, surrendered all rights to a 6-year-old he had adopted from Florida’s foster care system after the Department of Children & Families seized the boy, along with three foster children in McGuigan’s care.

The action was prompted, in part, by the allegations of an 8-year-old boy last February, who told his caseworkers that McGuigan had molested him.

Although the case was closed with “no findings,” it was not the only time that McGuigan has been accused of making improper advances toward children.

In 2000, Delray Beach police sought charges against McGuigan for lewd and lascivious acts after a teenager told police McGuigan showed him a pornographic picture of a child and asked the boy to perform sex acts. No charges were filed by prosecutors. In 2011, an adult man told the Margate Police Department that McGuigan had molested him when the accuser was a child growing up near Boston.

McGuigan is not the only member of his family to be linked to allegations of child sex abuse. His father, John J. “Sean” McGuigan, was sentenced to serve seven to 10 years at what used to be called Walpole prison in Massachusetts for rape and molestation, and is now a registered sex offender. Sean McGuigan had been a foster father, a volunteer for Big Brothers, and also had adopted a child in Massachusetts.

Neither Michael McGuigan nor his attorney, Larry S. Davis, returned calls from a Miami Herald reporter Friday.

The president of Broward House’s board of directors, Mark Budwig, who owns a Fort Lauderdale graphic design firm, could not be reached for comment.

Dean Trantalis, a prominent Wilton Manors attorney and former city commissioner in Fort Lauderdale who serves on the Broward House board of directors, dismissed the allegations as “second- and third-hand accusations” that had never resulted in any arrests or convictions.

“If Mr. McGuigan were convicted of crimes of this sort, then my position would be that it was inappropriate for him to head the agency of Broward House,” Trantalis said. “In all fairness to anybody who is accused of something, they have the right to defend themselves and be heard in a court of law.”

Based in Fort Lauderdale, Broward House offers HIV and hepatitis C testing, operates both assisted living and independent housing facilities, as well as case management, education and prevention programs. The agency’s most recent available tax filing, from 2010, shows it with a roughly $11 million budget. McGuigan was listed as grants officer that year, and earned $105,437.

The group’s CEO at the time, Angelo Castillo, earned $198,104. Castillo’s retirement last September opened the door for McGuigan, who was vice president, to be promoted to CEO.

Michael McGuigan’s name first surfaced publicly in 2009. That’s when a 7-year-old boy named Gabriel Myers hanged himself in the shower of a Margate foster home. Gabriel’s death outraged South Florida children’s advocates, and sparked a two-year investigation and hearings.