Girl school Professor Gilbert Thompson finds a baby

A headstrong young teacher in a private school in 1930s Edinburgh ignores the curriculum and influences her impressionable 12-year-old charges with her over-romanticized worldview.

Muriel Spark's classic novel The Prime of Miss Jean Brodie was adapted by Scottish Television into a seven episode television serial for ITV in 1978 that featured Geraldine McEwan in the lead role. From Wikipedia.

A girl from a boarding school finds a baby and has to keep it because she seems to be the real mother to everyone.

Polly Parrish, a clerk at Merlin's Department Store, is mistakenly presumed to be the mother of a foundling. Outraged at Polly's unmotherly conduct, David Merlin becomes determined to keep the single woman and "her" baby together.

An out-of-work professor gets a break from an old college buddy to teach at an exclusive girl's school. But events conspire against him: he finds an abandoned child which he takes under his wing, despite the school's rules against teachers having a family; and the girls in the school resent his replacing a handsome and popular teacher, and do everything in their power to get him fired.

This movie stars Peter Chen Ho as a male teacher in an all girls school. The girls are teens and, since they live there, are kind of tickled to see a male teacher. They don't particularly lust after him, but they kind of crush on him. The title of the film refers to a baby that Chen minded as a favor in a doctor's office, only to find the mother left him with Chen. Chen has to take care of the baby and, inevitably, has to bring him to school and hide him, as he lives there also.