Her hands were cuffed in front of her in court, where the indictment was unsealed. She later posted $75,000 bail.
Her husband is police chief of Spring Valley. He is "not implicated whatsoever," Rockland County District Attorney Thomas Zugibe said.
The 35-count indictment says that, beginning in July, Modica had intercourse with a 16-year-old, as well as oral sex with that boy and a 15-year-old. The judge issued orders of protection for the boys.
Modica, a former PTA president at Sloatsburg Elementary School, also is accused of drinking with many other children at her home and smoking marijuana with them in her car.
Modica would face a prison term of 1 1/3 to four years if convicted.
Ramapo Police Chief Peter Brower said the investigation began Dec. 31, when his department received a complaint in the mail. He said the students involved go to Suffern High School, which is also attended by at least one of Modica's four children, a 16-year-old son.
"You have to understand these are allegations," defense attorney Gerard Damiani said after the court session. "They're allegations from teenagers."
Damiani said Modica's character had never been questioned before. She is in good standing with the state bar association and has no prior criminal record, he said.
Until earlier this month, Modica was deputy attorney for the Town of Ramapo and the Village of Sloatsburg. She was not reappointed this year.
Damiani said that Modica and her husband, Paul, have separated, and that she is living with her mother in Nanuet.
Beth Modica was a Rockland County prosecutor in the early 1990s, but Zugibe said he sees no conflict in prosecuting her.
Zugibe said Modica's husband "was not involved, was unaware and was not present when the alleged acts occurred. ... I have only the greatest respect for Chief Modica." He would not comment on whether the couple's children were aware of the alleged crimes.
Paul Modica's lawyer, John Edwards, said, "Paul's sole interest at this point is protecting his children. ... He's trying to make sure the kids are impacted as little as possible."
Rockland County is north of New York City.
