Some people dream of having a baby girl or a boy.
It used to be those matters were left to chance, but not anymore.
Today more people are choosing the gender of their child, a practice that's raising some eyebrows.
The Johnson house is full of testosterone, with four boys.
Four months ago the "all male" streak was broken.
Baby Ava arrived, but not by chance.
"We wanted a girl and we did what we had to do to have a daughter," says Nolana Johnson.
The Johnsons went to the only fertility clinic in Texas that offers gender selection, the Sher Institute in Dallas.
Dr. Walid Saleh could almost guarantee them a girl.
Through in vitro fertilization, egg cells are fertilized by sperm in a lab.
After three days of growth in an incubator the embryos are taken out.
They are then biopsied and at that point doctors can tell how many female and how many male embryos they have.
"Comparative Genomic Hybridization" or "CGH" tests all 23 chromosomes in the D-N-A.
Hereditary disorders, birth defects and gender can all be revealed, allowing the mother to pick which embryo or embryos to transfer back into her body.
"When they called us that morning, they said, 'You have four girls and two boys.'" Johnson recalls. "I was very excited about that."
Nolana says doctors transferred three female embryos.
Dr. Saleh says more of his patients want to select the sex of their child, now 20 percent of I-V-F cycles in his practice.
Couples pay $10-15,000.
Tom Mayo, the director of the Maguire Center for Ethics and Public Responsibility at Southern Methodist University questions the practice.
"I think that the consensus is that it is potentially problematic, that it does raise serious ethical issues, but the balance so far favors autonomy on the part of the parents in making reproductive decisions that work for them," he says.
Mayo says time often changes minds.
"The technology will move even further, the numbers will increase," he explains. "Our comfort level will probably increase over time and we'll move on to other issues"
To people who disagree with his practice, Dr. Saleh says this:
"Number one: I don't make those babies. The miracle of life is the same. They are boys or girls on their own. The only thing we are doing is freezing the boys and transferring the girls or vice versa."
Dr. Saleh says he denies people who want a boy or a girl for cultural reasons.
His rule: You must already have at least one child at home, you can then select the opposite sex.
He calls it "family balancing".
"Through rebalancing, you maintain the 50-50 ratio between men and women and i really think that's what's important for society," Dr. Saleh says.
Nolana Johnson says "choosing" to have a little girl was a thoughtful process.
"I believe in God and I believe in science and I think they work together," she says. "I can't imagine anyone looking at Ava and saying, 'This is bad, you shouldn't have done this".
Nolana hopes that by talking about it she isn't judged, but can help other families yearning for that girl or that boy.
"If we can help another family, I want to help another family. This is amazing," she says.