This might have been true 25 years ago, but all of South and East Harlem has been experiencing steady gentrification for the last decade. Most of that is coming from young families, from my experience living in South Harlem.
(There are lots of attractions to the neighborhood: old buildings, pretty side streets, good food, convenient access to museums, and one of the most reliable subway lines in the system.)
Former Harlem resident chiming in here as an additional, concurring datapoint.
I didn't fit the traditional Harlem demographic (ex-FAANG employee, startup founder, etc) but found the neighborhood to have solid access to the rest of Manhattan, an increasing number of amenities, proximity to Central Park, and an overall appealing character compared to the increasingly sterile areas of Manhattan
If/when I move back to NYC I would certainly consider living in Harlem again.
(There are lots of attractions to the neighborhood: old buildings, pretty side streets, good food, convenient access to museums, and one of the most reliable subway lines in the system.)