Sort of. AFAIR it's a genuine "old wives tale". Shortly after the war in the UK there wasn't enough food to go round and the pig population was infested with worms. We couldn't afford to not eat them so the government issued directives that pork had to be extremely well cooked (to remove the danger of internal nastiness). "Older wives" passed this on to younger cooks and so on until it bacame a "given" that pork had to be well cooked. These days rare pork is no more dangerous than rare beef or lamb - freshly cut slices are the best as they only have bacteria on the surface which is quickly destroyed even by light cooking. Minced anything has a huge surface area and is much more prone to having live bacteria as a result. Chicken on the other hand is likely still to be infested (with Sam and Ella, that well known couple) and really does have to be well cooked.