Qld woman jailed for sexually abusing son

A Queensland woman jailed for sexually abusing her special needs son betrayed him and although she suffered horrendous treatment as a child herself, it was no excuse, a court has heard.

The middle-aged woman, who can't be identified, was on Friday sentenced to five years' jail in Brisbane District Court after pleading guilty to two counts of incest in 2015.

The court heard she had suffered through "deviant sexual practices" and extraordinarily harsh discipline as a child and gave birth after being raped by her stepfather.

Her background was described by Judge Julie Dick as "sad" and "dysfunctional".

"It doesn't excuse it. You are the mother of this child," she said.

The woman has been in custody for 17 months and will have her sentence suspended after serving 20 months.

She will remain on probation for three years and must undergo psychiatric treatment.