Of the people interviewed by the authors, 265 told of children fathered by members of the peacekeeping force, who came from at least 13 countries but mostly Uruguay and Brazil, according to a chart in the study.

“That 10 percent of those interviewed mentioned such children highlights just how common such stories really are,” they wrote. They noted that over the years, news organizations had reported anecdotal cases in Haiti in which “minors were offered food and small amounts of cash to have sex with U.N. personnel.”

The authors did not estimate the exact numbers of impregnated women or children left behind. But legal experts and aid workers say the problem has been pervasive, and that the United Nations has failed to assist the women.

The Bureau des Avocats Internationaux, a group of Haitian lawyers based in Port-au-Prince, has filed paternity suits on behalf of 10 children said to have been fathered by peacekeepers. Sienna Merope-Synge, a staff attorney at a Boston-based partner organization, the Institute for Justice and Democracy in Haiti, said the groups had approached United Nations officials in 2016 about securing child support for the mothers but had received none.

“The U.N. must be much more proactive,” she said. “It shouldn’t be on a woman in rural Haiti to seek transnational action for a man in Uruguay.”

Others were far more critical of the United Nations, seeing the Haiti study as another instance of what they called the organization’s male-dominated ethos. Paula Donovan, a co-founder and co-director of AIDS-Free World, a group that has frequently castigated the United Nations over sexual abuse and gender issues, said the study had corroborated her views.

“This research confirms that standard U.N. practice is to exploit women — from those subsisting in tents to those presenting at conferences — and then squash them like bugs if they dare complain about sexual abuse and threaten the U.N. patriarchy’s 75-year-old culture of entitlement and impunity,” Ms. Donovan said in a statement.