A woman has been found guilty of sexually abusing her own children.

She groomed her stepson, plied him with drugs and had sex with him between the ages of 11 and 14.

She also had sex with her husband while her daughter, who was around 10 years old, lay on the bed and watched, and on another occasion showed the girl how to use a vibrator.

The boy's father was jointly charged with several counts relating to the abuse of four children, to which he pleaded guilty.

The woman, who will not be named to protect the identity of the victims, pleaded not guilty to ten charges relating to her stepson and one relating to her daughter.

During the course of her trial she admitted to two counts of causing or inciting a child under the age of 13, her daughter, to engage in sexual activity.

Before she was found guilty by a jury yesterday, (Thursday February 21), her counsel Holly Gilbury laid out her defence.

Cross examining the woman's stepson, Ms Gilbury asked him if he could recall a pattern on her private parts caused by a skin condition, which he could not.

She said: "This distinctive feature that you would think would stick out in your mind, one that you think you would mention to police; he didn't describe it. He wasn't able to describe it."

Defending the woman, Ms Gilbury also mentioned that the defendant found penetrative sex painful.

Another factor of her defence was the claim that their home was open plan and the children all slept in the same room during a time the offences took place.

The woman also encouraged the male victim to go to counselling at one point.

Ms Gilbury said: "Why would someone who was grooming, sexually abusing and giving drugs to a young person encourage that person to go to counselling where they could tell them what happened?

"It just doesn't make sense, does it?"

Ms Gilbury submitted that the male victim was "confused" about the role his stepmother played in his life, and was unclear about certain details including his claim that his stepmother would sunbathe naked when according to the defendant and two of her daughters, she was unable to sunbathe because of a skin condition.

Ms Gilbury asked the jury: "He could not be sure about what happened, how could you be?"

As for the count involving having sex in front of her daughter, the woman maintained that she did not realise the girl had walked into the room, and shouted at her to leave when she did realise.

The couple will both be sentenced on Monday (February 25).

Read more on the trial here.