First thing, there is no concept of inherited sin in Islam. We are born without any sin or sinful conditions. Similarly if a child is born with any abnormal conditions, it is not a punishment of any sin of parents or forefathers.
Hazrat Mirza Ghulam Ahmad Qadiani (as)
The purification of one’s self is very difficult and yet salvation is based on the purification of self. God the Almighty says: Qad aflaha man zakkaaha; that is to say, he who purifies himself attains to success. But the purification cannot be attained to except with the grace of God. The inviolable law of God