In this June 5, 2014 photo provided by Children's Memorial Hermann Hospital, Dr. Kevin Lally, left, talks with Crystal Copeland, second from left, and her daughters Emily, second from right, and Caitlin Copeland in Houston. Lally is the pediatric surgeon
Eighteen years ago, Emily and Caitlin Copeland were born joined at the liver.
Now, on Tuesday, they celebrate their 18th birthday and a successful separation surgery that allowed them to lead normal lives and graduate as co-valedictorians from a Houston high school.
None of this was certain when Crystal Copeland, their mother, learned she was pregnant with conjoined twins, which occurs once every 200,000 live births.
Chief surgeon at Hermann Memorial Children's Hospital Dr. Kevin Lally says he too wasn't certain they would succeed when they took the 10-month-old girls into the operating room in April 1998 to separate them.
Caitlin notes turning 18 is exciting for everyone, but for them "it's just a really big blessing that we got to 18, considering what could have happened."