Answer: In MY opinion, I would consider PARAPHILIA an abnormal sexual behaviour.
Explanation: The term "abnormal" is used when something is pertaining to that which is irregular, in particular, behaviour that deviates from norms of social propriety or accepted standards of mental health.
PARAPHILIA can be defined as a sexual arousal in response to sexual objects or situations which may interfere with the capacity for reciprocal affectionate sexual activity or lead to clinically significant distress or impairment (e.g. are obligatory, require participation of non consenting individuals, lead to legal issues).
A behavior is considered ‘statistically unusual’ if it occurs among less than 16% of the population.
Examples of paraphilia given include voyeurism, sadism, masochism, exhibitionism, fetishism, pedophilia, frotteurism, and transvestism.