HOUSTON --Women undergoing in vitro fertilization usually transfer two or three embryos at a time, hoping to improve the odds of having a baby. But a Houston doctor is bucking the trend, saying one embryo at a time is best -- and he's offering to do a second embryo transfer free if his patients don't get pregnant the first time. Janet Pace has a three-year-old son but it took four rounds of in vitro fertilization with several embryo transfers at a time. She and her husband wanted one more baby. But this time, they transferred not three, not two, but just one embryo. "You think if it doesn't work with one, we've to do it all over again -- and that's the hard part," Pace said. But it did work. Pace is 27 weeks pregnant with one baby boy. "It is healthier for the baby and the mother to have a singleton," she said. More is better has been the attitude in IVF. "I've taken shots , I've had egg recovery; for most patients, IVF is not insurance covered, so they've paid money to do this and they think, well if I put more back I've got a better chance," said Dr. George Grunert with Fertility Specialists of Houston. But Dr. Grunert says IVF is more effective now. Today women have "the same pregnancy rate with one embryo that we used to have with four or five embryos 20 years ago but a lower complication in pregnancy," Dr. Grunert said. Fewer embryos mean fewer multiples fewer premature babies more likely to die or have disabilities. Grunert believes so strongly that one baby at a time is best that he gives his patients an unusual offer: "If it doesn't work, if you're one of the 50 percent of people who doesn't get pregnant, we'll transfer that second embryo for free, and we'll give you that second chance for pregnancy," he said. He's talking about women under 35, or women over 35 who have genetically normal embryos. For other women, there are cases when it's the right thing to transfer two or three embryos. Pace says, for her one embryo was the answer. "It's the right thing for our family" Pace said.