SAN FRANCISCO - The University of California needs a formal ban on professors dating their students, some members of the nine-campus system's governing board of regents said Thursday.

Regent Judith Hopkinson said she would like to see a policy developed that, in particular, would prohibit faculty from dating undergraduates.

''These young people are entrusted to the University of California and I think that we have a responsibility to honor that trust,'' she said.

UC's policies were propelled into the spotlight late last year when the dean of UC Berkeley's Boalt Hall law school resigned over an accusation of sexual harassment brought by a former Boalt student.

Former Dean John P. Dwyer resigned in November, acknowledging he had acted inappropriately but claiming the 2-year-old incident was consensual. The student, through her lawyer, later disputed that, saying she had been sexually assaulted by Dwyer after passing out after a night of drinking with Dwyer and other students.

UC has a policy banning sexual harassment, in compliance with federal law, and officials had been reviewing that as part of a routine update that began before Dwyer's resignation. Officials are looking at implementing a systemwide training program, part of which will start next month.

In the Boalt case, the woman's attorney has said the Berkeley Title IX officer, who is charged with ensuring the campus is complying with federal laws against harassment, was not helpful and said officials could not guarantee the student's name would be kept confidential or that she would be protected from retaliation.

For that reason, the attorney says, the student waited until she had graduated and taken the bar exam to file a complaint.

Berkeley officials say the Title IX officer did respond appropriately to the student. They say the woman refused to give her name or the name of the dean when she was told that a formal investigation would be launched if she did so. Administrators say they responded promptly when the woman filed a complaint last October.

On the issue of consensual relationships, UC has a 1983 faculty resolution that warns against the dangers of faculty having romantic relationships with their students and instructs a faculty committee to consider writing an addition to the faculty conduct code on the issue.

At the time, the addition did not materialize, although faculty reaffirmed the resolution in 2001 and later began working on a policy regarding dating.

Gayle Binion, chairwoman of the academic council, told regents that most faculty understand the ethical problem of dating a student.

''A sexual liaison with a student is just deemed to be inappropriate,'' she said.

But Binion said it's important for the university as an institution to have a clear statement on the issue. A draft is now being worked on and faculty will take up the issue at a Jan. 29 meeting.

Binion said there are some controversial issues to be negotiated, such as whether there should be different policies for undergraduates and graduate students.

Regent-designate Barbara Bodine said she agrees with zero tolerance of sexual harassment but warned against drafting too sweeping a ban on consensual relationships. That, she said, would be unenforceable in a system as large as UC.