EWTN Catholic Q&A
Question from JoAnn Downes on 04-15-2017:

was Eve the only woman made for Adam. If so when Cain killed Able where did Cain find a woman to have children with. Did Eve have more children an they intermarried.

Answer by Richard Geraghty on 04-24-2017:

Dear Joann,

Adam and Eve were the original man and woman. They had male children like Cain and Able but also must have had daughters. Otherwise males would have had no one to marry. But the future needs babies to grow up and be parents.

Dr. Geraghty