MANKATO, Minn. - One day after a KARE 11 Investigation exposed a legal loophole that allows teachers to legally have sex with some students, change is taking place. One teacher has resigned and state lawmakers are planning to introduce new laws to make student-teacher sexual relationships a crime, regardless of the age of a student.

RELATED LINK: KARE 11 Investigates: Teacher-student sex not always illegal in Minnesota

A Mankato mother wanted something to be done after she says her son, while he was an 18-year-old Mankato West High School senior, admitted to her he had sex with one of his teachers. He denied the relationship to school officials.

“From my point of view, if someone does not stand up, and make somebody accountable, then it's just going to keep continuing,” the mother said.

Mankato Police investigated, but said even if there was proof of sexual contact, due to the student's age of 18 at the time, it would not be criminal. So police ended their investigation.

But on the same day our KARE 11 Investigation aired, the Mankato West teacher resigned, according to the teacher's union and the school district. A district official also told KARE 11 the school re-opened its investigation into the allegations after receiving new information.

And now some lawmakers want to step in.

“I think what you have made very obvious to us is that we need to change the laws,” said Representative Sondra Erickson (R-Princeton), a former teacher who chairs the Education Innovation Policy committee.

Erickson plans to introduce a bill to make it illegal for teachers to have sexual contact with any K-12 student,regardless of age.

“It's important that we close this loophole and ensure that our children are always safe in our schools,”Erickson said.

Another lawmaker, Rep. Glenn Gruenhagen (R-Glencoe), who is a former school board member, also indicated he wants this law changed, because “a teacher is in a position of authority, responsibility and trust,” he said.

Minnesota has a law concerning sexual relationships involving a person of authority, but it doesn't apply to teachers if the student is 18 years old.

Since the Mankato West teacher resigned amid an internal investigation, by statute the district is directed to forward their information to the Minnesota Board of Teaching. The board will make the determination as to whether or not the teacher should lose her teaching license.