Educator blog post:

The current admissions system is based on a single test, on one day. That’s the way it’s been, for a long, long time. But in 1970 or 1971, someone decided to study the admissions policy for the schools (at that time the Bronx High School of Science, Brooklyn Technical High School, and Stuyvesant High School). The New York State legislature responded by passing the Hecht-Calandra Act, enshrining the existing test in law, and limiting an already limited alternate route (Discovery).

https://jd2718.org/2018/08/26/specialized-high-schools-some-comments-should-not-matter/