The objectives of this protocol are: 1) to determine the frequency of coagulation abnormalities in children with porencephaly or stroke as compared to healthy children, 2) to determine the frequency of coagulation abnormalities in children with porencephaly or stroke as compared to their family members, 3) to determine the frequency of coagulation abnormalities in mothers of children with stroke as compared to mothers of healthy children, and 4) to describe the exogenous conditions, which in concert with coagulation factors, may have led to the development of thrombosis in children with stroke.