Kelly and Gil Bates, who are evangelical Christians and do not believe in using birth control, are over the moon to be expecting another baby, who is due on Valentine's Day 2012.
The announcement came as the family, who range from 22-year-old Zach to 11-month-old Judson were filmed for ABC news. The couple from Tennessee were shownn on camera having an ultrasound to confirm the pregnancy.
Kelly, who home schools her younger children, had been taking hormones to help her carry a baby to full term after suffering three miscarriages, and is now over the moon to be expecting another baby:
'It feels more normal to me to be pregnant than not be pregnant. I'm happy holding a baby.'
Kelly, 44, has spent almost her entire adult life pregnant, but looks remarkably youthful.
Their massive brood includes Zach, 22, Michaela, 21, Erin, 19, Lawson, 18, Nathan, 17, Alyssa, 16, Tori, 15, Trace, 14, Carlin, 13, Josie, 12, Katie, 11, Jackson, nine, Warden, eight, Isaiah, six, Addallee, five, Ellie, four, Callie-Anna, two, and baby Judson.
The couple also told the programme they ultimately would like to have an even 10 girls and 10 boys, which would make them the largest American family, a title currently held by the Duggars, a reality TV family who Kelly, Gil and their children are good friends with.
'We just want to trust God, But at the same time, if there's already a life living, we don't want to deny medical help to a baby that's in trouble,' says Kelly.
The 18 children, plus mum and dad, share a five bedroomed house which Gil, 46, a tree surgeon, is planning to extend. They travel together in two family vans. The family go to the supermarket every other day, with their bill always reaching $250. They have five washing machines and four tumble driers to cope with the family's washing. They don't have a TV, preferring to play family games instead.
On the family's website (!) they say: 'We were told that having a house full of children would result in a ruined marriage, a frazzled and worn mom, a frustrated dad, and unhappy children. On the contrary, the children keep us feeling young and the responsibilities have driven us to more committed and meaningful relationships.
'We were told having a large family would send us to the poor house. Well, great expenses are required and that has increased our faith all the more. It has also taught us contentment and gratitude. We realize that having food, clothes, and living in America - no matter what our tax bracket might be - already makes us richer than most who live in the world.
What do you think about having a family this big?
Would you want to go through 19 pregnancies?
And how about home schooling while coping with that much washing and cooking? A sucker for punishment?