Vic woman avoids jail over child sex

A Melbourne woman told a 15-year-old boy their sexual relationship would be frowned upon, a court has heard.

Rebecca Nally, 26, pleaded guilty to two counts of the sexual penetration of a child under 16 over the sexual relationship she had with the teenage boy last year.

She has avoided jail time over her actions after she was sentenced to a two-year community corrections order and 150 hours of community service in the Victorian County Court on Wednesday.

Judge Barbara Cotterell said Nally's marriage had broken down around the time she shared a house with the teen and his brother in January last year.

During that time Nally invited the 15-year-old into her bedroom to sleep, and the pair later had sex.

On another occasion Nally again suggested he sleep in her room, before engaging in sexual acts with him.

The teen later left the house to live with his father, who found out about what had happened between Nally and his son.

The father asked Nally if it was true, and the then 25-year-old told the teen she planned to lie to his father.

Nally was unaware her conversation with the teen was on speaker phone and being listened to by the father.

"You told him that your relationship would be frowned upon," Judge Cotterell said.

"You spoke about the message you planned to send his father."

The father reported Nally to police, and she was arrested after agreeing to come to the police station.

"You admitted the allegations and the fact that you knew the complainant was 15 at the time," the judge said.

"This is clearly very serious offending."

Nally has been placed on the registered sex offenders for life.