Lady Gaga and Michael Polansky's Baby Is a Girl, Name Revealed

Lady Gaga and Michael Polansky's baby is a girl named Rose ... TMZ has learned.

According to the birth certificate obtained by TMZ, Rose Bean Polansky was born June 9 at 11:19 PM at Cedars-Sinai Medical Center in Los Angeles.

It's unclear where the name Rose Bean originated from ... however Gaga has a large rose down her spine that she got to commemorate her performance of "La Vie En Rose" in the film "A Star is Born." The middle name Bean may have been inspired by singer/activist Carl Bean -- whom her hit "I Was Born This Way" pulled inspo from.

The baby was delivered by Dr. Robert Katz, the OB-GYN to the stars ... the same doctor who helped Ciara and Russell Wilson welcome their daughter, Sienna.

As we reported ... Gaga was recently photographed holding her daughter close to her chest while walking with Polansky and a friend in Northern California. The couple has been spending private family time away from the spotlight.

Gaga and Polansky remain engaged and are not married ... despite a recent report claiming they had secretly tied the knot. Sources with direct knowledge told us earlier this month that close family members had seen the couple together and knew they had not gotten married.