LOS ANGELES, CA (Catholic Online) - According to pediatric surgeon Dr. Holly Hedrick, Allison is the smaller but tougher twin. Amelia is the larger twin but currently remains in intensive care.

Surgeons separated the Tucker girls during a seven-hour operation in November. The girls had been joined at the lower chest and abdomen, and shared a chest wall, diaphragm, pericardium and liver but are expected to live "full, healthy and independent lives."

The prognosis for the twins is very positive. The surgery was the 21st separation of conjoined twins performed at the hospital and involved about 40 medical staff members.

The twins' mother, Shellie Tucker revealed her joy at the successful operation on her online blog.

"Today it is a time to celebrate, to be thankful, to appreciate, to praise, and to enjoy this weight lifted off our shoulders," she wrote.

"The surgery went better than expected. The girls did amazing. The surgeons were able to separate the girls and close them with the skin they grew over the last five months.

"After the girls left us yesterday I had a sense of calm and strength comes over me. These girls are going to do big things in life!

"Greg and I are thrilled that our daughters have been given this remarkable gift by the amazing team from The Children's Hospital of Philadelphia.

"We are so grateful for the support and encouragement that the medical team, our families and our friends have given us during this long journey."

On her blog, the proud mother wrote how she married her husband, Greg Tucker in 2009 and at first had issues with fertility.

After having their first son, Owen, she wrote: "Our chances of having a second baby were very slim. We tried month after month with no success."

After fertility treatment, she and her husband were overjoyed to find out they were pregnant again. However, their 20-week ultrasound was the first sign that there was something wrong.

Conjoined twins occur once in every 50,000 to 60,000 births, and most are stillborn. About three-quarters of such twins are female and are joined at least partially in the chest, sharing organs.

The tuckers can put this behind them now as their baby girls now have a better chance at a normal life.

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