Conditional tags should be a basic feature. This feature being missing from basic accounts is unfair to people of sexual minorities who's user experience may be negatively impacted by the inability to combine tags. For example, the only existing way to blacklist solo tags with the exception of female is [if male, -solo]. I'm personally a lesbian and having this show up by surprise can sour the mood significantly.
Without a separate tag for the solo gender variants, people are entirely unable to separate images that may make them uncomfortable as sexual minorities.