A Long Island, New York, woman has carried and delivered her identical twin sister’s baby — a boy she says she will consider her nephew.

In 2009, Allison Ardolino Dinkelacker was 30 weeks pregnant with her first child when she learned she had breast cancer, Fox News reports.

She needed to start chemotherapy immediately and her son Dylan was born by emergency caesarean section at 31 weeks.

When she decided to have a second child, her twin sister, Dawn Ardolino Policastro, offered to carry her child.

Dawn gave birth to her nephew, Hudson, on August 5.

“How can we begin to thank you for the tremendous generosity and sacrifice you have so willingly bestowed these last few months?” Allison wrote on her Facebook page.