My Response for this claim consists of my personal writtings and the footnotes descriptions of the Holy Verses from my Holy Quran, which was translated by Sheik (Minister) Abdallah Yusuf Ali.
Anti-Islamic Claim: 49.Marrying the wives of adopted sons? It is important that Muslims can marry the divorced wives of adopted sons [Sura 33:37], yet it is forbidden to adopt sons [Sura 33:4-5].
My Response: Let us look at Noble Verse 33:37 "Behold! Thou didst say to one who had received the grace of Allah and thy favour: 'Retain thou (in wedlock) thy wife, and fear Allah.' But thou didst hide in thy heart that which Allah was about to make manifest: thou didst fear the people, but it is more fitting that thou shouldst fear Allah. Then when Zaid had dissolved (his marriage) with her, with the necessary (formality), We joined her in marriage to thee: in order that (in future) there may be no difficulty to the Believers in (the matter of) marriage with the wives of their adopted sons, when the latter have dissolved with the necessary (formality) (their marriage) with them. And Allah.s command must be fulfilled."
Let us look at Noble Verses 33:4-5 "4. Allah has not made for any man two hearts in his (one) body: nor has He made your wives whom ye divorce by Zihar your mothers: nor has He made your adopted sons your sons. Such is (only) your (manner of) speech by your mouths. But Allah tells (you) the Truth, and He shows the (right) Way.
5. Call them by (the names of) their fathers: that is juster in the sight of Allah. But if ye know not their father's (names, call them) your Brothers in faith, or your maulas. But there is no blame on you if ye make a mistake therein: (what counts is) the intention of your hearts: and Allah is Oft-Returning, Most Merciful."
There is no contradiction in the Noble Verses above.
Where does it prohibit the Muslims to adopt sons in Noble Verses 33:4-5 ??!! There is a little fraud on your part Mr. Jochen Katz !. I suggest for you to actually read the Noble Verses that you critisise first before you attack them. Otherwise, you will be a big fool without even knowing it.
For Noble Verse 33:37 above, it was about Zayd, the son of Harithah, one of the first to accept the faith of Islam. He was freedman of Prophet Muhammad peace be upon him, who loved him as a son and gave him in marriage to his own cousin Zaynab. The marriage however turned out unhappy.
Zaynab the high-born looked down upon Zayd the freedman who had been a slave. And he was not comely to look at. Both were good people in their own ways, and both loved the Prophet, but there was mutual incompatibility, and this is fatal to married life. Zayd wished to divorce her, but the Prophet asked him to hold his hand, and he obeyed. She was closely related to the Prophet; he had given a handsome marriage gift on her marriage to Zayd; and people would certainly talk if such a marriage was broken off. But marriages are made on earth, not in heaven, and it is no part of Allah's plan to torture people in a bond which should be a source of happiness but actually is a source of misery. Zayd's wish indeed the mutual wish of the couple was for the time being put away, but it became eventually an established fact, and everybody came to know it.
All actual facts are referred to Allah Almighty. When the marriage is unhappy, Islam permits the bond to be dissolved, provided that all interests concerned are safeguarded. Apparently there was no issue here to be considered. Zaynab had to be considered, and she obtained the dearest with of her heart in being raised to be a Mother of the Believers, with all the dignity and responsibility of that position.
For Noble Verses 33:4-5 above, if a man called another's son "his son", it might create complications with natural and normal relationships if taken too literally. The truth is the truth and can not be altered by men's adopting "sons". Adoption in the technical sense is not allowed in Muslim law. Those who have been "wives of your sons proceeding from your loins" are within the prohibited degrees of marriage; but this does not apply to adopted sons.
Calling a stranger kid an "adopted son" is not prohibited in Islam. Making him dear to your heart and treating him as a real son is not prohibited in Islam. But that kid would never have the rights of the real son. He will never become your real son, nor can he inherit anything from you.
Please visit Did Prophet Muhammad really marry his daughter in law? for more details.