Considering that he is young, a mechanical valve is the right choice for him, unless and until he has some contraindication for the use of mechanical valve in terms of bleeding diathesis. However, mitral valve repair is always considered a better option than the mitral valve replacement and therefore you must speak to your cardiac surgeon regarding possibility of the repair in your case.Prosthetic heart valves definitively have a chance of stroke, but if your anticoagulation is well maintained, then these chances lessen to a high degree. The stroke can be related to either over anticoagulation in which, the blood becomes thin and there may be bleeding inside the brain or when the anticoagulation is inadequate and the blood becomes thick, when some blood clots may form on the valve and may dislodge and lodge in the brain. However, if anticoagulation is maintained at adequate levels of around 3-3.5, then the chances of stroke are reduced. Definitively some chance of stroke is present.This is an open heart surgery and in that sense certainly this is a complicated surgery and of a much bigger magnitude than any other run of the mill surgery. However, these surgeries are now-a-days being performed on a routine basis and in most good centres, would carry a risk of around 2-3%, unless and until there are other complicating factors.We do not give such recommendations as to which is the best hospital. I think most hospitals now-a-days are well equipped and undertake this kind of surgery on a routine basis.The hereditary cause for mitral valve prolapse has not been proven but there seems to be some suggestion that this may infact have a genetic basis, but one can not take any precautions on this front even for the offsprings and therefore one should not worry on that account.