With a committee vote scheduled Tuesday for Robert F. Kennedy Jr.'s confirmation to lead the Department of Health and Human Services, Senate Democrats are demanding more details on the nominee's connections to vaccine lawsuits and are saying Kennedy should promise to recuse himself from any vaccine-related decisions if confirmed health secretary.

The demands came in a letter released Monday by Sens. Ron Wyden and Elizabeth Warren, after Kennedy told the lawmakers that he planned to divest his financial stake in one ongoing vaccine lawsuit to his adult son who practices law in California.

The description matches that of his son, Connor Kennedy, who is an attorney at Wisner Baum, a California-based law firm that is representing plaintiffs in a civil lawsuit against Gardasil, a vaccine intended to protect against HPV and deemed safe by the Centers for Disease Control and Prevention.

Warren and Wyden, the top Democrat on the Senate Finance Committee, called the arrangement of allowing his son to collect future referral fees in the lawsuit "troubling" and "plainly inadequate."

"The arrangement outlined in your Ethics Agreement Amendment is plainly inadequate, as it would appear to allow an immediate family member to benefit financially from your position as Secretary," wrote Wyden, D-Ore., and Warren, D-Mass.

It's not clear whether the letter released Monday by the Democrats would impact Kennedy's confirmation as health secretary, which could still be pushed through by the Republican majority. It is possible, however, that Republican senators with concerns about Kennedy's nomination -- including Sen. Bill Cassidy -- could use the Democrats' request to slow the confirmation process.

"Your past of undermining confidence in vaccines with unfounded or misleading arguments concerns me," Cassidy, R.-La., a medical doctor, said in his opening remarks during a hearing last week on Kennedy's nomination.

He added, "Can I trust that that is now in the past? Can data and information change your opinion? Or will you only look for data supporting a predetermined conclusion? This is imperative."

The Senate Finance Committee, chaired by Cassidy, is scheduled to vote Tuesday on Kennedy's nomination.

Warren and Wyden said they couldn't trust Kennedy's financial disclosures were "accurate and complete" because they don't lay out how many cases Kennedy referred to Wisner Baum and whether vaccines were involved.

Wisner Baum has said it has not paid the nominee for any vaccine-related cases, as the current Gardasil case is ongoing.

Wyden and Warren said any involvement is a direct conflict of interest if he were to become health secretary because of his oversight of vaccines.

"By using your authority and bully pulpit as Secretary to sway the outcome of the litigation and secure a big judgment or settlement, you would increase the chances of a large payout for yourself," they wrote.