I did a deeper study in Psalms 51:5 and Romans 5:12-21 and even though we are conceived and born into a world where sin that was brought about by one man, Adam, now makes all of us a sinner at some point in time and only when sin is revealed to us do we become a sinner needing that of Gods grace. The law revealed sin in us and grace pardons our sins with that of Gods righteousness that makes us come from Spiritual death unto that Spiritual life through Christ. Adam did not die physically as we know he lived to be around 903 years old. It was a Spiritual death that Adam died in as in all of us because of his disobedience and that of ours.
(Psalms 51:5 Behold, I was shapen in iniquity; and in sin did my mother conceive me.)
I was formed (shapened) in my mother’s womb as I was conceived in that of my mother living in a sinful world and delivered to that of a sinful world, but iniquity was not found in me until the laws of sin were revealed to me did I also become a sinner as even I grew to transgress the law.
Romans 5:
(12 Wherefore, as by one man sin entered into the world, and death by sin; and so death passed upon all men, for that all have sinned
Well then, sin entered the world through one man and through sin Spiritual death and thus Spiritual death has spread through the whole human race because everyone has sinned.
(13 (For until the law sin was in the world: but sin is not imputed when there is no law.)
Even though sin is in the world by that of one mans disobedience it is not imputed (us making a mistake) in us until it is revealed to us by now God's law, but the former by His prophets up until the time of Moses. We, no matter what age in or out of the womb, are innocent until we are taught that of what we are transgressing in the law is sin. This is why Jesus said in Matthew 19: 14 But Jesus said, Suffer little children, and forbid them not, to come unto me: for of such is the kingdom of heaven. Other words it is the innocent that the kingdom of God belongs to.
(14 Nevertheless, death reigned from Adam to Moses, even over them that had not sinned after the similitude of Adam's transgression, who is the figure of him that was to come.)
Sin existed in the world long before the Law was given. There was no law from the time of Adam to Moses so no one could be accused of the sin of lawbreaking. Yet Spiritual death reigned over all from Adam to Moses even though their sin, unlike that of Adam, was not a matter of breaking a law.
(15 But not as the offence, so also is the free gift. For if through the offence of one many be dead, much more the grace of God, and the gift by grace, which is by one man, Jesus Christ, hath abounded unto many.)
Adam prefigured the One to come, but the gift itself considerably outweighed the fall. If it is certain that through one mans fall so many Spiritually died, it is even more certain that divine grace coming through the One man, Christ Jesus, came to so many as an abundant free gift.
(16 And not as it was by one that sinned, so is the gift: for the judgment was by one to condemnation, but the free gift is of many offenses unto justification.)
The results of the free gift also outweigh the results of one man's sin for after one single fall came judgment with a verdict of condemnation now after many falls comes grace with its verdict of acquittal.
(17 For if by one man's offence death reigned by one; much more they which receive abundance of grace and of the gift of righteousness shall reign in life by one, Jesus Christ.)
If it is certain that Spiritual death reigned over everyone as the consequence of one man's fall it is even more certain that One man, Christ Jesus, will cause everyone to reign in life who receives the free gift that he does not deserve of being made righteous.
(18 Therefore as by the offence of one judgment came upon all men to condemnation; even so by the righteousness of one the free gift came upon all men unto justification of life.)
Again, as one mans' fall brought condemnation on everyone so the good act of One man, Christ Jesus, brings everyone to life and makes them justified.
(19 For as by one man's disobedience many were made sinners, so by the obedience of one shall many be made righteous.)
As by one man's disobedience many were made sinners so by One man's, Christ Jesus, obedience many will be made righteous.
(20 Moreover the law entered, that the offence might abound. But where sin abounded, grace did much more abound
When law came it was to multiply the opportunities of falling, but however great the number of sins committed grace was even greater.
(21 That as sin hath reigned unto death, even so might grace reign through righteousness unto eternal life by Jesus Christ our Lord.)
Just as sin reigned wherever their was Spiritual death so grace will reign to bring eternal life thanks to the righteousness that comes through Christ Jesus our Lord.