LITTLE ROCK, Ark. -- It will be a happy Mother's Day for an Arkansas woman: She's pregnant with her 18th child.

Michelle Duggar, 41, is due on New Year's Day, and the latest addition will join seven sisters and 10 brothers. There are two sets of twins.

"We've had three in January, three in December. Those two months are a busy time for us," she said, laughing.

The Duggars' oldest child, Josh, is 20, and the youngest, Jennifer, is 9 months old.

The fast-growing family, which has a Web site, lives in Tontitown in northwest Arkansas in a 7,000-square-foot home. All the children, whose names start with the letter J, are home-schooled.

Duggar has been pregnant for more than 11 years of her life, and the family is in the process of filming another series for Discovery Health.

The new show looks at life inside the Duggar home, where chores -- or "jurisdictions" -- are assigned to each child. One episode of the new show involves a "jurisdiction swap," where the boys do chores traditionally assigned to the girls, and vice versa, Duggar said.

"The girls swapped jurisdictions, changing tires, working in the garages, mowing the grass," she said. "The boys got to cook supper from start to finish, clean the bathrooms," among other chores.

Duggar said she's six weeks along and the pregnancy is going well. She and her husband, Jim Bob Duggar, said they'll keep having children as long as God wills it.

"The success in a family is first off, a love for God, and secondly, treating each other like you want to be treated," Jim Bob Duggar said. "Our goal is for each one of our children to be best friends, and everybody working together to serve each other makes that happen."

The other Duggar children, in between Joshua and Jennifer, are Jana, 18; John-David, 18; Jill, 16; Jessa, 15; Jinger, 14; Joseph, 13; Josiah, 11; Joy-Anna, 10; Jeremiah, 9; Jedidiah, 9; Jason, 7; James, 6; Justin, 5; Jackson, 3; and Johannah, 2.