Univision May Face Ad Boycott : Television: Two national advertisers leave the Spanish-language network over a commentator’s allegedly sexist remarks. Channel 34 could be affected.

A New York-based flap over allegedly sexist remarks about Puerto Rican “welfare mothers” threatened Monday to spread into a nationwide advertising boycott of the Spanish-language Univision network and its regional TV stations, including KMEX Channel 34 in Los Angeles.

Remarks by commentator Carlos Montaner, aired two months ago on Univision’s weekly “Portada” program (an hourlong newsmagazine cast in the mold of ABC-TV’s “20/20”) sparked demonstrations that drew more than 500 pickets at Univision’s New York-New Jersey station, WXTV Channel 41, in late November.

By New Year’s Eve, that furor had escalated to a withdrawal of two major national advertisers from Univision: Coca-Cola and Goya Foods, a major processor and distributor of food products targeted to a Latino market.

“This is something that has been simmering for more than a month,” Esther Renteria, president of National Hispanic Media Coalition, told The Times on Monday.

Before going to WXTV and Univision’s advertisers, the Puerto Rican community leaders in New York, who worked with the National Hispanic Media Coalition, tried unsuccessfully to get both WXTV’s station management and Univision’s parent company, Hallmark Cards Inc. of Kansas City, Mo., to sanction Montaner. Had the network acted against Montaner the way that CBS News did when it suspended “60 Minutes” commentator Andy Rooney last year for allegedly prejudiced comments about gays, the advertiser boycott might not have been necessary, according to Renteria.

She said that the coalition, which is headquartered in Los Angeles, plans no specific actions against KMEX, Hallmark’s Los Angeles outlet, but that the action against Univision should ultimately have some impact on that station. KMEX management could not be contacted for comment on Monday.

Montaner, a Cuban-born newspaper columnist whose work is syndicated throughout Latin America and Europe as well as the United States, told “Portada” ’s audience last Nov. 5 that he believed Puerto Ricans fare worse than other Hispanics in America because “thousands of single mothers,” go on welfare at a tender age or live with men who leave them with even more children, thus aggravating their economic hardship even more.

Most of the Puerto Rican population in the continental U.S. is concentrated in the New York-New Jersey area, though a small portion of the 3.3 million Hispanic-Americans who live in Los Angeles and Orange counties are of Puerto Rican descent, according to 1990 U.S. Census Bureau estimates.