Sexual feelings, attractions, fantasies and desires affect virtually all people from (at least) puberty onwards. The average age of puberty for girls in the UK is 12 to 13, 13 to 14 for boys. In common with other aspects of development, the age at which puberty occurs varies widely from person to person. It is normal for the onset of puberty in different individuals to start as young as 8 or to be delayed until 16 or 17.

The age at which people first begin to act on their sexual interests also varies widely and can be affected by a large range of factors including biological development, hormone levels, cultural factors, religious and moral views, upbringing, self-esteem, education and socio-economic status.

Wide variation in age at sexual debut is part of the normal spectrum of adolescent development. By the end of the teenage years most young people in the UK will have had sex. The average age of sexual debut in the UK is 16 – 17. While most young people nowadays have not had sexual intercourse by the time they turn sixteen, between a third and half have.

A young person under the age of 16 (and, in certain circumstances, 18) is regarded as a child for the purposes of Child Protection Guidance (see: Scottish Borders Child Protection Procedures), the aim of which is to protect children and young people from harm.

People of any age, who are subjected to exploitative, coercive or abusive sexual situations, may be in real danger. Where someone under the age of 16 is involved in such situations it is important that they are, as far as possible, protected from harm (see: is it consensual, is it abuse?).

Most sexual activity is likely to be consensual. Young people who are consensually sexually active may also be at significant and, sometimes, life-threatening risk of harm if they are unable to access services to protect them from unwanted pregnancy and sexually transmitted infections. There is strong evidence that, where young people do not believe a service to be confidential, they will not use the service and may come to significant harm as a result (see: is it consensual, is it abuse?)