If the law is passed, Huntington Beach would be the first city in the state to have such a program and possibly the first government agency in the state to require that both cats and dogs receive microchips, officials said.

"The idea is to produce fewer unwanted animals and therefore less euthanizing and therefore more cost savings to society," said Councilman Keith Bohr, who proposed the law.

When the council first discussed the plan in September, about 30 pet owners, breeders and animal shelter workers held a heated debate about the issue. Opponents argued that it would be difficult to enforce, expensive and a violation of their rights.

The latest version of the proposal would require cats and dogs to be spayed or neutered at four-months-old, but pet owners could opt out of the program by paying a fee. The microchip would still be required.

Opponents who have organized as Pet Owners Want Equal Rights, or POWER, plan to rally against the proposal at the corner of Main Street and Yorktown Avenue before the meeting, group members said.

"Do they think that only rich people should have pets?" said resident Diane Amendola. "That is an elitist attitude. I am a senior citizen and I can't afford to buy my way out of the ordinance."

Some have also asked if it is a conflict of interest that Bohr's wife is on the board of Save Our Strays, a main proponent of the ordinance.

Bohr said the idea for the ordinance came from a tour of animal shelters with Karen Chepeka, president of Save Our Strays. The nonprofit group offers a low-cost spay, neuter and microchip program for pet owners in Huntington. Bohr's wife, Elizabeth Propp, has been a volunteer board member for two years.

City Council members and City Attorney Jennifer McGrath said Propp's work is not a conflict of interest and that Bohr does not need to abstain from Monday's vote.

Peter Scheer, executive director of the California First Amendment Coalition, said there are no legal concerns about a conflict of interest, but recommended that Bohr disclose his wife's position and abstain from the vote.

The city has received more than 500 emails and faxes about the spray, neuter and microchip ordinance, officials said.

Councilman Don Hansen, who plans to vote against the law, said that most of the letters to the city have not been in support.

"It is none of the city's business to regulate how you handle your pets," he said. "It is my choice to do with my pets how I see fit."

If the law is approved, pet owners would have a 30-day grace period to show proof of sterilization and microchipping. If they do not comply, they would be fined $150. The penalty would be increased by $50 every 30 days up to a maximum of $500, officials said.

Monday's council vote is the first for the ordinance. If passed at a second reading and no appeals are filed, the law would go into effect within 30 days.