Rep. Trent Franks, an Arizona Republican who is among the most conservative members of the House, said he would resign his seat after House officials learned that he had asked two female employees to bear his child as a surrogate.
Franks's announcement came as the House Ethics Committee said it would create a special subcommittee to investigate Franks for conduct "that constitutes sexual harassment and/or retaliation for opposing sexual harassment."
His resignation, which Franks said is effective Jan. 31, will end the ethics investigation.
Franks said in his statement that the investigation concerns his "discussion of surrogacy with two previous female subordinates, making each feel uncomfortable."
While Franks's statement left the circumstances of the "discussion" murky, three Republicans familiar with the allegations said that he had asked the staffers, who worked for him at the time but have since left his office, if they would serve as a surrogate mother for his child. A spokesman for Franks did not respond to a request for comment on that claim.
In his statement, Franks said he never "physically intimidated, coerced, or had, or attempted to have, any sexual contact with any member of my congressional staff."
"However, I do want to take full and personal responsibility for the ways I have broached a topic that, unbeknownst to me until very recently, made certain individuals uncomfortable," Franks said, adding, "I deeply regret that my discussion of this option and process in the workplace caused distress."
Franks explained in his statement that he and his wife have long struggled with infertility. After having twins with a surrogate, the couple sought additional children, he said.
House Speaker Paul D. Ryan's office said in a statement Thursday that Ryan (R-Wis.) had been briefed on "credible claims of misconduct" by Franks last week, after the House general counsel was contacted about the allegations and investigated them.
Franks did not deny the allegations when Ryan confronted him, according to the speaker's statement. Ryan told Franks he should resign, and said he would refer the matter to the House Ethics Committee, his statement said.
"The speaker takes seriously his obligation to ensure a safe workplace in the House," the statement said.
The Franks revelations came on the same day that Sen. Al Franken (D-Minn.) resigned his seat after multiple allegations of sexual misconduct and as the House Ethics Committee opened a separate probe into Rep. Blake Farenthold (R-Tex.).
The committee initially launched an investigation into Farenthold in September 2015, but it was "significantly delayed" because the committee could not get "key witnesses other than Representative Farenthold" to testify, according to the committee's statement.
Farenthold's former communications director, Lauren Greene, accused Farenthold in 2014 of making sexually charged comments designed to gauge whether she was interested in a sexual relationship. Greene filed suit through the formal complaint process with Congress's Office of Compliance.
It was revealed last week that Farenthold used $84,000 in taxpayer money to settle the lawsuit. Farenthold has denied wrongdoing in the case.
This week, Greene spoke publicly about her experience for the first time since making the accusation. In interviews with CNN and Politico, she described the significant professional backlash she faced after filing a lawsuit against Farenthold.
The House Ethics Committee has requested Greene to cooperate with the investigation and appear before the panel. Prior to coming forward, Greene had declined, wanting to move on from the matter. But she has now agreed to cooperate with the investigation, said her attorney, Les Alderman.
"We're trying to get that done before the holidays, over the next few weeks," Alderman said.
Farenthold said in a statement Thursday that he is "relieved" the House Ethics Committee will continue investigating the matter, saying he is "confident this matter will once and for all be settled and resolved."
Franks has served in the House since 2003 and is known as a fierce opponent of legal abortion, recently sponsoring a bill banning abortions after 20-week gestation that passed the House. He is also an outspoken critic of the Senate's filibuster rule, blaming it for blocking conservative bills.
Franks is also a member of the House Freedom Caucus, a hard-right faction that has often clashed with Republican leaders.
He considered a run for Senate in 2012 but dropped out suddenly. He continued as chairman of a House Judiciary subcommittee and as a member of the House Armed Services Committee.
While Franks was on the floor Thursday voting on a stopgap funding bill and other measures, he appeared to be consoled by a number of fellow Republicans. At one point, Franks and four colleagues locked arms and bowed their heads in an apparent prayer.
Franks said he was compelled to resign after concluding that he would be unable to endure the ethics probe "before distorted and sensationalized versions of this story would put me, my family, my staff, and my noble colleagues in the House of Representatives through hyperbolized public excoriation."
"Rather than allow a sensationalized trial by media [to] damage those things I love most, this morning I notified House leadership that I will be leaving Congress as of January 31st, 2018," he said. "It is with the greatest sadness, that for the sake of the causes I deeply love, I must now step back from the battle I have spent over three decades fighting."
Arizona's 8th Congressional District, which stretches northwest of Phoenix, leans Republican by 13 points, according to the nonpartisan Cook Political Report. President Trump defeated Democratic nominee Hillary Clinton in the district by 21 points last year; Franks did not face a Democratic opponent.
Under Arizona state law, a special election must be called if there is a vacancy more than six months before a regularly scheduled election.
Names of potential Republican successors include Kimberly Yee, the state Senate majority leader currently running for state treasurer, and Phil Lovas, a former state representative, according to multiple Arizona GOP operatives.
Ed O'Keefe contributed to this report.