iStock/deng qiufeng(INDIANAPOLIS) — Twins with different birthdays is a rare occurrence. Twins with different birth years even more so. But a woman in Indiana has done something almost unheard of – she has given birth to twins born in different decades.“We are still in shock,” Dawn Gilliam, mother to the twins, told ABC News’ Indianapolis affiliate station WRTV alongside her partner Jason Tello at Ascension St. Vincent Carmel Hospital. The twins also weren’t due for another 7 weeks so their special birthday was a big surprise to the parents.“We were surprised how big they were,” Gilliam said. “We joked about it before knowing that we were in labor.”Joslyn Grace Guilen Tello was born at 11:37 p.m. on Dec. 31, 2019 weighing 4 pounds 11 ounces and 17.9 inches long while her brother, Jaxon DeWayne Mills Tello was born exactly 30 minutes later on the next day, Jan. 1, 2020, weighing 4 pounds 4 ounces and 18.1 inches long.Joslyn and Jaxon’s birthdays were also notable to Ascension St. Vincent Carmel because Joslyn was the very last baby born there in 2019 and Jaxon was the very first baby born there in 2020.Joslyn, Jaxon, Jason and Dawn are all doing well. Copyright © 2020, ABC Audio. All rights reserved.