Miranda and Josh Crawford of Charlotte, North Carolina always wanted to have children. Unfortunately, starting a family was difficult for the couple, and they turned to IVF. In 2008, doctors transferred two embryos into Miranda's uterus, and one survived: Baby Joslyn was born the following year.

Knowing that they wanted more children, Miranda and Josh turned once again to IVF one year later. This time, however, they were in for quite the surprise.

For more about this special family, watch this video:

Two embryos were once again transferred into Miranda's uterus, and just six weeks into the pregnancy, doctors told the couple that they were expecting twins. But when she went back to confirm the number of babies growing in her belly, the ultrasound was more clear: there were not two beating hearts on the screen, but rather four.

Not only had both embryos survived, but they had split in two, creating two sets of identical twins!

Miranda and Josh were shocked, to say the least. "The math here is mind-boggling," explains Dr. Jani Jensen, a physician in the department of reproductive endocrinology and infertility at Mayo Clinic. "The patient likely only had about a 60 percent chance of getting pregnant at all, and with that, we expect that at least half of the time when two embryos are placed in the uterus, only one will continue to develop, so even twins are more of the exception, not the rule." Though Miranda dealt with complications, including gestational diabetes, her pregnancy went quite well overall, and in February of 2010 she welcomed Jackson and James ...

... and Mia and Madison.

Miranda and Josh quickly came to terms with their family of seven, and agreed that teamwork was the key to making everything work. "We are simply happy that all four are alive and well," Miranda said.