my cat has never been able to meow

Hi my 2 year old cat has never been able to meow, its been like this since birth. do you know any reason why shes like this? I uploaded a video of her trying to meow on youtube - IMG 2084 1 - YouTube

Hello     I am unable to access the video but understand from your post that your cat is 'doing the motions' of a meow without any sound coming out.  Some cats simply don't meow very much and that is normal for them, but that may not explain the silent attempts to meow that you appear to be seeing.  What you describe appears to be rare, so your vet may want to make absolutely sure that this behaviour is a genuine attempt to meow and not, for example, a sign of nausea, so-called 'gipping' (e.g. secondarily to pancreatitis), jaw pain, toothache and so on.  They may also want to rule out diseases putting pressure on the vocal folds e.g. cancer / a goitre such as those seen in hypothyroidism / nasopharyngael polyps (benign growths / outpouchings of the lining of the nasopharax) / enlarged lymph-nodes and so on.  Other causes might include a stretched oesophagus (megaoesohagus) which is often seen on x-ray; cancers (less likely at this age) but also damage to the recurrent laryngael nerve (the nerve involved in maying the purr happen), which is only sporadically reported in cats.  Again, my understanding is that this is usually seen in older cats secondarily to some disease process or age-related changes, but apparently it can be seen congenitally (from birth), or secondarily to a foreign body or surgical intervention in that area.   In conclusion then, it is well worth reporting this to your vet in order that they can investigate if it is appropriate to the context in which your cat is presenting.  Please will you let us know if you find anything out?