FORT WORTH - After struggling to get pregnant and then turning to science, one mother recently gave birth to two sets of twins, which is something doctors call a rare event.

Suzanne Steece gave birth to three boys and one girl.

"Andrew was the first born, and then Benjamin, then Ethan and then Savannah," Steece said.

The babies were born one minute apart.

"They came at different times," Steece said. "They just were pulling babies ... out."

And while Steece's children may sound like a case of quadruplets, that isn't exactly the case.

"My mom is an identical twin and my husband was a fraternal twin," she said. So, I had a set of identical twins and a set of fraternal twins."

While Andrew and Ethan are identical twins, Savannah and Ben are fraternal twins. Doctors said that is extremely rare.

"They're so cute," Steece said. "I could just look at them all day long."

Steece struggled to get pregnant for a year.

"I have a moderate case of endometriosis, so I had some issue with that," she said.

After one month of taking the lowest dosage of a drug that increases ovulation, Steece got pregnant.

"Our first try and bam we got pregnant, and found out a couple of weeks later we were pregnant with four," she said.

The odds of having a set of identical and fraternal twins at the same time are so rare, doctors say the odds don't even exist.

"With this case, they had three eggs and then one of them split and they ended up with the twins," said Sandy Rhodes, manager of the neonatal intensive care unit at Harris Methodist Fort Worth Hospital.