lets see it this way, girls are purely matrilineal lines and boys purely patrilineal ones

i finally solved the way to find the chances a boy keeps an exclusivily patrilineal line in the future:

if the population is to keep he will have two counting childs which each will have another two and so on

so lets consider a coin toss game, a tail is a boy and a head a girl

the game to find the chances is simple:

toss a coin two times and for every tail you get two extra tosses, you keep playing till you run out of tosses

thise are your chances of having a patrilineal line in the future

but the tossing game in the end can be reduced or simplified to:

you have one toss and for every tail you get an extra toss, you keep playing till you run out of tosses and lose

exactly for the boys in here your chances to get a patrilineal line in the future are 2 elevated to the number of generations

now if even the hole globality dont have the chances to keep a patrilineal line in the case of boys and a matrilineal in the case of girls, humanity cant exist in 64 generations

so is it human reproduction a myth or probability fails in this case