Vaginismus

Some women experience difficulties with penetration. Their vagina contracts and  prevents penetration. It's not that they don't want sex: it's a physical condition but a conditioned reflex, sometimes resulting from a psychological fear of penetration.

How is it treated? 
Through injections of paralysing botulinum toxin that block the muscles of the perineum.
However, this treatment isn't easily available in the UK.

Results 
According to the majority of sexologists, this technique is aberrant! A woman who fears penetration won't be cured at all. The muscles which tighten the vagina are simply paralysed by the botulinum toxin. It's an extremely invasive treatment (involving an intra-vaginal injection) and in a woman who already fears penetration, it can even make the problem worse in the long term.