Attorney Richard Emanuel represents Van McKenzie Adams who was convicted of having sex with two students in New Haven.
Adams, who taught Latin at Hill Regional Career High School, was 40 at the time. The students in the second-degree sexual assault case were 16 and 17.
Emanuel told the justices Thursday that the state law under which Adams was convicted is unconstitutional and "overly broad."
"I am not here to assert that teachers have a fundamental constitutional right to engage in sexual intercourse with their students," Emanuel said. "They should not exploit their position to coerce students into relationships involving sexual intercourse."
Emanuel pointed out that the court had previously ruled that people age 16 or older are "deemed to be adults for sexual purposes." He said such conduct is "protected by the right of privacy."
Assistant States Attorney Bruce Lockwood argued on behalf of the state that a sexual relationship between a teacher and a student "cannot be consensual" because of the power and authority teachers have over students.
"The state has a legitimate interest in providing a safe school environment for elementary and high school students," Lockwood said. He added that prohibiting teachers from having sex with their students is part of this approach.