There are two answers to this question which depends on whether one answers from a Catholic or Protestant perspective. I will attempt to give what the Scriptures actually say.
1. Sinners for what we have DONE and what we ARE
Note the instruction in 1 John 1:8, 10 -
8 If we say we have no sin [Noun], we deceive ourselves, and the truth is not in us.
10 If we say we have not sinned [Verb], we make Him out to be a liar, and His word is not in us.
Note that here sin is both a noun and a verb; that is, we are sinners because of what we are and because of what we have done. The fact that we are sinners before we even did anything is also expressed in Ps 51:5 -
Surely I was sinful at birth, sinful from the time my mother conceived
David is saying that we all have sinful tendencies and enjoy what we should not (see also Paul's discussion in Rom 7). According to Rom 3:23 - we have all sinned (done something wrong) as well.
2. Who is Guilty?
Note that while we are all sinners at birth before we did anything wrong, we are still innocent of committing sin (but it usually does not take long!). However, we do not inherit Adam's sin as guilt because this is a firm law in the Torah:
Deut 24:16 - Parents are not to be put to death for their children,
nor children put to death for their parents; each will die for their
See also Eze 18:20. Thus, whatever we inherit from Adam it is not his guilt for we had no part in that guilt.
3. What we inherited
The condemnation we inherited from Adam is the sinful tendencies not the guilt. That is, we inherited a fallen human nature that is naturally attracted to sin.
The word translated "condemnation" in Rom 5:18 is κατάκριμα (katakrima) which only occurs three times in the NT and all in the book of Romans, namely, Rom 5:16, 18, 8:1. Note the extended passage in Rom 5:16-19 -
16 The gift is not like that which came through the one who sinned;
for on the one hand the judgment arose from one offense, resulting in
condemnation, but on the other hand the gracious gift arose from many
offenses, resulting in justification.
17 For if by the offense of the one, death reigned through the one,
much more will those who receive the abundance of grace and of the
gift of righteousness reign in life through the One, Jesus Christ.
18 So then, as through one offense [o]the result was condemnation to
all mankind, so also through one act of righteousness [p]the result
was justification of life to all mankind.
19 For as through the one man’s disobedience the many were made
sinners, so also through the obedience of the One the many will be
Paul is contrasting the sinful nature of man inherited from Adam with the righteousness of the second (perfect) "Adam" namely Jesus Christ.
He concludes this lengthy discussion in Rom 8:1-3 by using the same word:
Therefore there is now no condemnation at all for those who are in
Christ Jesus. For the law of the Spirit of life in Christ Jesus has
set you free from the law of sin and of death. For what the Law could
not do, weak as it was through the flesh, God did: sending His own Son
in the likeness of sinful flesh and as an offering for sin, He
condemned sin in the flesh,
We do not inherit guilt from Adam but do inherit sinful flesh (= human nature) from Adam. However, being a sinner by nature (as opposed to action) makes just as much a sinner as by action and in need of salvation. This is one of the distinguishing features of Jesus - he was perfect in all senses and was untainted by sin (Heb 7:26), did not have a sinful nature and thus, did not need a savior Himself.
Back to Romans 5:15-19
This passage in Rom 5 has a repeated structure contrasting the first and second Adam as follows:
|Rom 5 ref
||Second Adam = Jesus
||Sin passed to ALL men
||Sin reigned until Jesus
||MANY (= all) died (compare Rom 3:23)
||Grace abounds to MANY (= all)
||One sin brought condemnation
||The gift brings followed many trespasses brought justification
||One man's trespass death reigned
||Those who receive grace, righteousness reins in the life
||One trespass brought condemnation for All men
||Disobendience of one man the many (= all Rom 3:23) were made sinners
||Obedience of one man the many (= all, Rom 3:24) wil be made righteous
This is confirmed by similar teaching elsewhere:
- Rom 11:32, For God has consigned everyone to disobedience so that He may have mercy on everyone.
- 2 Cor 5:14, For Christ’s love compels us, because we are convinced that One died for all, therefore all died.
- 2 Peter 3:9, The Lord is not slow in keeping His promise as some understand slowness, but is patient with you, not wanting anyone to perish but everyone to come to repentance.