According to Alabama law, in which Mayella and her father reside,
A person commits incest if he marries or engages in sexual intercourse with a person he knows to be, either legitimately or illegitimately:
(1) His ancestor or descendant by blood or adoption....
When incest involves an adult and a child it is considered to be a form of child sexual abuse. So, in the situation of Bob Ewell and his daughter Mayella, it is evident that Mayella, albeit the age of majority at nineteen years old, has been subjected to her father's incestuous acts for years. For, during Tom Robinson's testimony on the stand, he alludes to the situation between Mayella and her father:
"She reached up an' kissed me 'side of th' face. She says she never kissed a grown man before an' she might as well kill a n-----. She says what her papa do to her don't count...."
If, then, there have been incestuous acts as implied by Mayella, Bob Ewell would be guilty of a Class C Felony in Alabama. With a conviction for this lowest class of felonies, the sentence is no less than two years and no more than twenty years. Fine are no more than $5000.
In addition, Ewell could be tried for sexual abuse of a child since Mayella has been forced to commit this incest before her age of majority. However, since she is now a legal adult, Mayella would not be taken by the Department of Human Services and placed in a foster home as is customary procedure for minors.