Gaby

When Abe Simpson visited the local travelling carnival at Shelbyville, he met an attractive female prostitute, with whom he had a brief sexual relationship. When the carnival travelled away from Shelbyville, she discovered she was pregnant with Abe's child. A year later, the carnival returned, and Abe discovered that she had given birth to their son.

Unmarried and ashamed, she and Abe abandoned their infant son at the Shelbyville Orphanage, where he would be later adopted by the Edward Powell and his wife Mililani Osler. They named him Herbert Powell, who when on to be the founder of Powell Motors in Detroit, Michigan.

Description
Young, beautiful and attractive, it's no wonder that Abe fell for her at first sight. The only thing Herb seems to have inherited from her is his hair colour.