SAN FRANCISCO — Two federal judges in California have arrived at opposite conclusions on whether the state’s first-of-its-kind law prohibiting licensed psychotherapists from trying to change the sexual orientations of gay minors violates the Constitution. The measure remains clear to take effect on Jan.1.

US District Judge Kimberly Mueller refused on Tuesday to block the law after concluding that opponents who have sued to overturn it were unlikely to prove the ban on ‘‘conversion’’ therapy unfairly tramples on their civil rights.