Does intracytoplasmic sperm injection lead to a rise in the frequency of microdeletions in the AZFc region of the Y chromosome in future generations?

Microdeletions in the AZFc region of the Y chromosome are found in oligo- a nd azoospermic men, These mutations were genetically lethal before the intr acytoplasmic sperm injection (ICSI) era but they can nowadays be transmitte d to next generations via ICSI, We have tried to ans,per the question,'Does ICSI lead to a significant rise in the frequency of these microdeletions i n future generations?', by developing a mathematical model for Y-linked mut ations with two variables (fitness and mutation frequency), To illustrate t his model we have made estimates according to three imaginary scenarios, Us ing the assumptions described, the model predicted that the frequency of mi crodeletions in the AZFc region would increase in each generation until a p lateau was reached, The higher the fitness, the higher the plateau and the later the plateau would be reached. Taking realistic estimates fur fitness (0.5) and spontaneous mutation frequency (0.0001), the maximum increase in men with microdeletions mould be twofold, This maximum would be already rea ched after five generations, However, if the fitness of these men were impr oved and approached 1.0, the mechanism of selection would disappear and fin ally all men mould have the deletion in the AZFc region, Because of the ass umptions in these scenarios, these estimates have limitations, The model pr esented shows that the rise in the frequency of men with microdeletions in the AZFc region in future generations would be limited as long as the fitne ss of these men remained limited.