When you look at a mother, you are looking at the purest love you will ever know. That rings true for the mother-daughter bond between Kristine Casey and Sara Connell.

Their touching journey began several years ago, with unfortunate heartbreak. Sara and her husband Bill struggled to expand their family.

After going through 6 cycles of in-vitro fertilization, Sara was overjoyed to hear that she was pregnant with twins! Tragically after she went into premature labor, the babies were stillborn.

When she managed to become pregnant again, she miscarried. The couple then struggled with the fact that Sara could not carry a pregnancy to term.

The couple didn't want to give up their dreams of having a family, so they began to look at hiring a surrogate to carry their baby for them.

That's when Kristine Casey, Sara's mother who was 60 years old at the time, made an offer that left them surprised.

Continue to the next page to find out what it was.

Kristine had carried her pregnancies without incident and was prepared to do it again for Sara and her husband. Kristine is already the mother to 3 girls, and claimed that the happiest moments of her life was being pregnant with them. She wanted to be her daughter's surrogate and help bring her grandchild into the world.

Despite her age, Kristine wasn't worried about carrying a baby. After being examined by her doctors, they agreed. The told her that the worse symptoms she would feel would be fatigue.

That's when she learned back into her chair and laughed.

"Tired!" Sara recalled her saying. "I was tired when I had no help and two children under five to run after every day. I'm retired now "” I don't have to do anything. If fatigue is the big factor, I think I can handle it."

It wasn't long after that that Kristine was caring her grandson. She compared the experience to babysitting for nine months.

At the end of the surrogacy, Kristine delivered her grandson, Finnean, a healthy 7-pound baby boy at the Prentice Women's Hospital in Chicago. Kristine also became the oldest woman in Chicago's recorded history to give birth.

At last, at the age of 35 Sara had finally got the family she waited so long for.  

The family's unconventional journey has been told in Sara's new memoir, Bringing in Finn: An Extraordinary Surrogacy Story.

The book recounts how her mother and herself had drifted apart of the years, but reconnected after the loss of the twins.

"Our reconnection had come as a surprise, with a will of its own, fueled perhaps by the same phenomenon that allows mothers to lift cars to save their infants. 'There is going to be joy at the other end of this pain,'" she said.

6 years later, he is the light of his mother's and grandmother's lives.

Sara doesn't hide the fact that his grandmother was the one that brought him into the world.

'I said, "My tummy had a broken part, [so] for you they took the parts from mommy and daddy and you got to go into Grandma's tummy, and I was with you every day until you were born."' Sara told the boy as he became curious about where he came from.

He simply thought it was cool, and didn't ask anything more than that.

This mother's act of selfless love grew the bond between her and her daughter even stronger than it was previously.

"My gratitude really can't even be described in words," Sara said.

Sources: Liftable / Info Channel / Little Things / Daily Mail