An American woman could be forced to register as a sex offender after appearing topless in front of her step-children in her own home. Tilli Buchanan, from Utah, was charged with three counts of misdemeanour lewdness involving a child after appearing topless along with the children's father in their home last year. Ms Buchanan's lawyers are contesting the charge, arguing it is unfair to treat men and women differently for baring her chest. She said she and her husband were working in their garage in late 2017 or early 2018 and removed their shirts to prevent them from getting dusty.   She told the court that when the children, aged nine and 13, entered the garage she “explained she considers herself a feminist and wanted to make a point that everybody should be fine with walking around their house or elsewhere with skin showing”. “It was in the privacy of my own home. My husband was right next to me in the same exact manner that I was, and he’s not being prosecuted,” she said after the court hearing. The charge occurred after child welfare officials began an investigation involving the children on an unrelated matter and the children’s mother reported the incident to authorities because she was “alarmed.” If convicted, Ms Buchanan could be required to register as a sex offender for 10 years. Her husband was not charged. Ms Buchanan's lawyers appeared in court on Tuesday to ask a judge to overturn the charges, arguing that they are unconstitutional. The lawyers cited a previous court ruling that overturned a Colorado ban on women going topless in public. However the prosecution said that in the US, nudity is commonly understood to include women's breasts. The judge in the case, Kara Pettit, declined to rule immediately on the case, saying it was “too important of an issue”. A ruling is expected in the next few months.