Yes, in sex offences, but as a reliable science, it remains highly questionable.
If someone is an expert in any particular field or specialist subject, their opinion is admissible as evidence, whereas an ordinary persons opinion on a specialist topic is not. An 'Expert Witness', as is Mr Mullins, can give evidence stàting his opinion, and if unchallenged, his opinion would have to be treated as factual...
To be specific, his would be considered ' factual opinion'...