There are risk factors which contribute to the development of strawberry marks, hemangiomas. Girls have a higher risk of developing them than boys. So do babies born prematurely or to a mother who’s advanced in age. Twins or triplets also have a higher chance of having a birthmark called a hemangioma. If you had a procedure such as amniocentesis during the pregnancy, there’s also a risk your baby will develop strawberry marks or hemangiomas. Port wine stains and congenital melanocytic nevi do not have risk factors, nor are race or ethnicity contributing factors.