The Qur’an accuses us Christians to have altered biblical texts.
In respect of the second half of Romans 7 I consider this accusation to be justified.
In Romans 7:13 the Greek “original text” should not have a comma between αμαρτια and δια, nor between “sin” and “through”, because punctuation symbols did not exist, and αμαρτωλον means sinner not sin. Taking this into account, the text reads: “Did that which is good, then, become death to me? By no means! However, sin is shown to be sin through what is good. My doing becomes deadly, like that of the boundless sinner, through sinning against the commandment”. Verses 15-17 read as one continuum (which is possible because verses were not introduced until the 16 century) “If I do not understand by (learned, legal) doing I do not want to do it but I hate this doing, but if I do it, I do what I do not want to do, I recognise that the law is good, if I no longer obey it, then sin is living in me.”  And 19:20 reads (in joined up reading) “Not if I do what is good (the divine law) or do not want to do what is evil, but if I do not want to act accordingly, if I no longer obey, then sin is living in me.” Translated like this the above texts no longer point to a state of general brokenness and therefore no longer be used to justify original sin.

Answer:

Catholic teaching on original sin has its roots in Romans 5:12. The translation this is based on is the old Vulgate version: in quo omnes peccaverunt … “In which all have sinned” refers either to “a man” = Adam, or to “sin” - peccatum. Romans 7 is not generally used in doctrinal texts, only in some exegetical traditions. In Romans 5:12 the syntactical relation in the Vulgate text is highly likely not to be the same as in the Greek original (although it is not entirely impossible), because the Greek eph‘ hô is most likely to relate to ho thanatos: “the death, after which all have sinned” ; this is not possible with the Latin in quo (masculine or neuter) with mors (feminine). Most modern explanations of Romans 5:12 also assume the reference to be to ho thanatos. Original sin is included in St. Paul’s argument, because he does not understand the Genesis narrative to be a historic story about Adam. Rather, where the Hebrew Bible refers to ha-Adam, or in Greek to ho anthrôpos, Paul generally understands this to be the corporate story about “hu mankind”. This is also Paul’s understanding when Genesis 3 talks about “man”. And this is precisely the modern understanding of original sin: It refers to the sin which separates man from God, lastingly without his individual and personal sin.