Varicose veins - those ugly twisted veins that seem to bulge out of your legs - are not, and have never been, caused by crossing your legs.
Varicose veins are a result of weakened valves in the veins of your legs. Healthy valves keep blood flowing around the body. When these valves stop working, blood collects in your legs and pressure builds up - resulting in weak, large, and twisted veins (aka varicose veins).
A variety of factors cause weakened valves, including age, pregnancy and obesity. Simple genetics also play a big role, so I would just sit back and relax...with you legs crossed!
