The gender equalization in law happened through the 1980's and 1990's, at a time when salaries at large law firms were dramatically increasing due to the limited supply of graduates from which large law firms source their entry-level hires. The key difference is that law schools, being generally very progressive places, took aggressive steps to fill their classes with approximately equal numbers of men and women. And the field, being very progressive itself, embraced that trend.

It's also interesting to note that when it comes to LSAT scores, men outnumber women 2:1 in the top percentile. This is very similar to the gender gap in the top percentile of the Math SAT. Law schools tend to simply ignore that slight distinction, relying on the fact that women tend to have higher GPAs, so an index combining GPA and LSAT tends to result in roughly equal numbers of men and women. And in practice, it's a theoretical difference that has basically zero impact in the real world. Yet, people repeatedly hold up differentials in the Math SAT to justify gender gaps in STEM more extreme than the differentials in the Math SAT itself, as evidence that men are somehow more suited for STEM jobs.