男生要有大姨父才公平
[nán shēng yào yŏu dà yí fù cái gōng píng]
Playfully referring to societal or familial fairness, this could be a humorous twist indicating that for things to be equal ('fair'), there needs to be an aunt's husband (a metaphorical figure often symbolizing external perspectives or arbiters in certain cultural contexts) even for males.