“This spring has been nightmarish for the Jewish community,” said Dan Rosenberg Asmussen, chairman of The Jewish Community in Denmark. “The proposal takes as a starting point that Jews are child molesters.”

A ban would “make it difficult for the next generation of Jews to maintain a religious life in Denmark,” he added.

“Some rituals are central to identity and belonging. Circumcision is one of them,” said Waseem Hussain, an imam from the Danish Islamic Center in Copenhagen, adding of the proposed ban: “It shows a willingness to submit religious freedom to other liberties. Next up for discussion could be the right to wear a veil, to pray, to read the Bible or go to church on Sundays.”

A possible age limit has been a simmering issue on the political agenda in Denmark, but no major party has sought to push it forward. Pressure has come instead from campaigning groups like Intact, which started the petition.

Of nine political parties in Parliament, three — including two in the governing coalition — have taken the rare step of letting lawmakers choose independently how to vote on the issue. Two parties are in favor of an age limit and four will vote against.

A string of Danish organizations working on health or children’s rights discourage circumcision on ethical grounds, but have not found reason to advocate an outright ban. Indeed, there is evidence pointing in the other direction: The World Health Organization has found that circumcision reduces the risk of HIV by 60 percent for heterosexual males.

Mr. Khader, the lawmaker who favors an age limit, is Muslim. He said he made up his mind about the issue in 2004, when he faced family pressure to have his newborn son circumcised.