Accusations are just that, not necessarily fact, not convictions in a court of law. Still, it’s stunning that repeated allegations that Michael McGuigan made inappropriate sexual advances toward children didn’t raise any red flags for the board members of Broward House. The agency is Broward County’s oldest and largest HIV and AIDS service center, serving more than 6,000 people, including children, with the AIDS virus, as well as those who need drug treatment.

In fact, most board members were so unfazed that they recently elevated Mr. McGuigan to Broward House’s CEO, then later declined to suspend or remove him from the leadership position.

Mr. McGuigan, 53, resigned the post last week, once many of the agency’s funders, including Broward County and the state Department of Children & Families, threatened to withhold money. That shouldn’t have been the deciding factor. The safety of Broward House’s young, vulnerable clients should have spurred the board to act.

It’s true — Mr. McGuigan has not been charged with or convicted of any of the accusations. In 2000, police in Delray Beach sought to charge him with lewd and lascivious acts after a teen said Mr. McGuigan showed him a pornographic picture of a child and asked the boy to perform sex acts. Prosecutors did not file charges.

But he was criticized in a highly publicized case. In 2009, young Gabriel Myers lived in Mr. McGuigan’s licensed foster home. Gabriel, 7, had been molested while living with grandparents in Ohio. But he acted out in Mr. McGuigan’s home, as many traumatized children do. Gabriel was sent to another foster home, where he hanged himself.

A task force report criticized the agency for allowing Mr. McGuigan to punish Gabriel for how he behaved. During the course of the investigation of Gabriel’s heartbreaking death, a man from the Boston area made decades-old allegations that Mr. McGuigan had molested him as a child. In May 2011, DCF and the Broward Sheriff’s Office took custody of Mr. McGuigan’s son, then 4, whom he had adopted from foster care, in addition to three other children in his foster home. Ultimately, the adopted son was returned, but child-welfare authorities had jurisdiction.

In January, DCF filed a petition asking a judge to permanently sever Mr. McGuigan’s parental rights to the child. The next month, caseworkers with ChildNet, the privately run foster-care agency, told a judge that a boy, 8, had accused Mr. McGuigan of molesting him. That investigation was closed with “no findings.” This year, DCF requested, and Mr. McGuigan agreed, to sever his rights to his adopted son. He also has relinquished his foster care license.

The disturbing messiness of Mr. McGuigan’s tenure as a foster parent and adoptive dad should have tipped the balance against his acquiring a position that puts him in direct contact with children. Yet he had high-profile defenders, including Angelo Castillo, who retired as Broward House’s CEO in September, and Dean Trantalis, a former Fort Lauderdale commissioner, who serves on the board.

But wasn’t there an iota of concern? Two board members resigned, but, according to Mr. Castillo, DCF informed him that “no action was required until and unless charges were brought.” This demands investigation. After all, DCF is the same agency that sought to remove Mr. McGuigan’s adopted son. Broward House’s board members need to prove they are worthy of the responsibility they have been given.