no, its not true. in fact marrying a person of same blood group
may have some benefits of its own.
like less chances neonatal jaundice
in the newborn.
but any mother who has a negative blood group if conceives with a fetus with a positive blood group, it may have some problems for the fetus especially for the second fetus (if the elder sibling also had a positive blood group).
may be you need to confirm from the medical records if your mother and father had same blood groups of was your father O+. in this case your mother might have needed anti D antibodies
hope i have answered your question
Dr. Amit Kumar