Steve's girlfriend was used for an experiment when she was 9 months pregnant (you're the baby). Her body was just found and taken to the Avengers tower for the data they can. They find out who the woman was and realize it's Steve's girlfriend. They thaw us out and somehow you (the baby) are still alive but they have to act fast and take you out of your mother's corpse before you die. Steve watched in horror, they have to do skin to skin with Steve instead of your mother. You look exactly like Steve.