Sources close to the family tell us ... Shayanna Jenkins-Hernandez -- who has a previous child with the late New England Patriots star -- welcomed a healthy baby in a Rhode Island hospital on June 16.

There were rumors that Aaron was the biological father (the product of frozen sperm) -- but that's NOT the case.

We're told the father of the child is Dino Guilmette, an amateur boxer from Providence. We're told both parents are excited for the happy and healthy baby.

Jenkins kept the pregnancy under wraps until last month ... saying, "I couldn’t be a luckier woman to have such a perfect little girl that’s prepared to become the best big sister, and even more blessed to welcome another babygirl to our home."

Congrats!!