THis joke is the based on idea that a man made many babies to other woman then problem is how her daughter can marry to a boy , but daughter is also not his biological child. this is a funny humorous adult joke.
gal desperately wanted to get married but when she introduced hr partner to
hr parents, her father would just say dont marry hm. Y? the gal askd, he is ur
half brother hr dad replied.... The same story happend 3 times. The gal then angrily went to hr mom nd said 'where were u all the timem when dad was busy
making babies' her mom said dont worry u can marry any of your Boy friends....
He is not your biological father