Autistic children and young people can face particular challenges in their sexual development. For many professionals in health, education, social care and justice, questions around harmful sexual behaviour remain especially complex. Research shows that autistic young people are not more likely than their peers to display such behaviour, yet they are consistently over-represented in referrals, creating uncertainty about how best to respond. This book brings together research, case studies and professional insight to provide an evidence based framework for practice. It explores the factors that shape sexual development and the circumstances that can lead to harmful behaviour, while emphasising the importance of recognising and supporting positive and healthy sexuality. Introducing an autism specific socio-ecological model, it guides practitioners through assessment and intervention, the role of psychosexual assessment and the need for tailored, child-centred sex education. The result is a rigorous and practical resource designed to build confidence, clarity and compassion in professional practice.