The Reason This Heartwarming Story of Twin Love Is Going Viral

We know that siblings share a strong bond, but the bond between twins is undeniable — especially for Dawn Ardolino-Policastro and Allison Ardolino Dinkelacker.

In 2009, Allison was pregnant with her son Dylan when a stage three breast cancer diagnosis at 30 weeks totally caught her by surprise. She began chemotherapy immediately, but at 31 weeks on her 33rd birthday, a sonogram revealed that the baby wasn't moving, so an emergency C-section was performed, and a healthy baby boy was born.

After six years of being cancer-free, Allison and her husband addressed always having wanted a second child, but because the cancer was hormone positive, Allison wouldn't be able to carry another baby — enter Dawn, and the most selfless gift a person could give.

Dawn generously offered to carry a child for her twin sister, resulting in a very special maternity photo shoot, and she recently gave birth to a healthy baby boy, Hudson William.

Allison's thank you note on Facebook couldn't have been more sweet.

Our new son Hudson William Dinkelacker has arrived and he would not be here if it weren't for my amazing sister! . . . I have said this before, but I have to say it again. Dawn, you amaze me! You are my hero and I have never been more proud of you. You deserve a medal of courage, of compassion, and of selflessness . . .

We cannot thank you enough for the gift you have given us. Although biologically this child will be made up of the two of us, we certainly hope that the strength, selflessness, and power you have shown are traits that he takes from you during his life. Not many people have the ability to make someone else's dream come true. But you have done so, and with extraordinary thoughtfulness, openness, and sensitivity.

It's obvious that many people in your life think you are terrific. But probably no one knows the full extent of your caring and generous nature quite like we do.

Dawn, we thank you for everything from the bottom of our hearts. We are and always will be eternally grateful!! What we are most grateful for is the gift you have given to Dylan, the gift of being a big brother, a dream that we all had and that you made come true!!!

Scroll through to see the sweet sister photos — especially the sneaky one of the baby's gender, which Dawn kept a secret from Allison the whole time!