First, the objection to the fact that some of His forefathers were born out of wedlock, and in OT it was a shame even for  future generations to have such a person as a greatgrand father. This objection was made by 'Khosroshahi'.
  Then the fact that we are proud of His noble Blood, while virtue is supposed to be better than nobility (a righous beggar vs. a not so rightous upper class man) And it can be objected that even if we believe in admiring someone for good actions of His ancestors, then it must be a greater glory to have a good  person in your family linage than a rich one.
  Any answer?

I should read some books first. But it may take some time. Who or what is "Khosroshahi"?

Maybe its just me, but your question doesn't make sense to me.  Are you speaking of Jesus?

Are you saying that because in His linage through Mary there is some ancestor that was guilty of sin?

It is my understanding that in the Old Testament, those people of God were not held to the same standards because the law was not given to them yet.  

Jesus was completely human, meaning He was just like any other human being born at that time concerning His lineage, that is what makes Him so loveable in my eyes.  It was not as if God just placed a tiny infant down on earth to live.  No, God allowed a miraculous conception within the womb of a woman that had a human lineage; ancestry with inherited properties shared with others of  her bloodline.   Remember too, He also had a DIVINE NATURE.   Something your 'Khosroshahi' seems to forget about.  

He was totally man and God at the same time.  God is perfect, and He created Mary perfect because of the roll she had.  She was a vessel that held God for nine months, she was created perfect, God's masterpiece, and it is she that we should admire for her obedience to God, in accepting this roll. Because she was to hold God within her, she had to be perfect, thus she was created perfect.   Although God created her full of grace, she still had free will and could have said no. God who knows all things, knew she would accept her roll. He knew this from the beginning of time.  I suppose He could have formed her from the earth, as He did with Adam and Eve, but that was not His will, He wanted her to have a human lineage.  

Why are you even reading what this Khosroshahi writes if you are studying to be Baptised anyway?  

Not even sure if I helped you above, since I am not sure of your question.  Sometime I have a problem reading here and the different ways people express themselves.  I admit I am limited in the way I see things.  Hopefully someone else will come here and explain better than I just tried to do.  

Oh, thanks for your explanation!

On thinking again on the question, in order for God to send His only son with two natures one human and one Divine, it was the Will of God the Father that Jesus should have a lineage, and since all men are sinners except for the Virgin Mary, we can not expect perfection in the bloodline.

There is no doubt a deeper and more meaningful way to explain this to you, and hopefully someone will come along who can. In the meantime, blessings from above  coming your way.