they used opposite genders

Not necessarily. For IBM PCs that was true, but my UltraSPARC had a differently-gendered serial port which was very annoying because neither standard straight nor null-modem cables worked. It was a DB-25, carrying two ports.

Those connectors were used for a lot of different things, with no autonegotiation no nothing. At least the pinout for port A was compatible with the standard DB-25 one-port pinout, just with different gender.