All people have inherited a sin nature from the first humans, specifically from Adam. The key questions involved here include, "What is sin?" and "What does it mean to inherit sin?"
What is inherited sin?
First, sin is defined as anything that falls short of God's perfect standard or glory. Romans 3:23 reads, "for all have sinned and fall short of the glory of God." It is also defined as breaking or transgressing the law of God, since John wrote, "Everyone who makes a practice of sinning also practices lawlessness; sin is lawlessness" (1 John 3:4).
Our sins include both sins of omission and sins of commission. Sins of omission are sins we commit due to our failure to do something we should. For example, instead of standing for something that is right, we remain silent. Sins of commission are sins we actively commit. When we tell a lie, we actively sin. Both types of sin fall short of God's glory.
Second, what does it mean to inherit sin? The word inherit refers to receiving something passed down from one generation to the next. In contrast to the idea that people are born neutral and without the stain of sin, Scripture indicates we are born with a sin nature that is inherited from our parents and their parents before them.
Because of Adam and Eve's disobedience, sin has been an "inheritance" for all of their descendants. Romans 5:12 tells us, "Therefore, just as sin came into the world through one man, and death through sin, and so death spread to all men because all sinned." We inherit our sinful nature similar to the way we inherit our parent's physical characteristics. David wrote, "Behold, I was brought forth in iniquity, and in sin did my mother conceive me" (Psalm 51:5).
As a result of inherited sin, we are sinful in nature and sinful in practice, both. We commit sins because we were born with the nature to do so. Very few would deny that people make mistakes in this life, yet many do not wish to accept the biblical view that people are born as sinners. Yet the best explanation for the universal practice of sin in our world is that it is part of our human nature. This does not excuse us from sin, but it does explain why we sin.
On a positive note, this problem of inherited sin has a solution. Paul told Timothy in 1 Timothy 1:15 that "Christ Jesus came into the world to save sinners, of whom I am the foremost." Though we may feel we are the worst sinner in the world, Jesus came to save us. To "save" us includes forgiving us from our sins. "In him we have redemption through his blood, the forgiveness of sins, according to the riches of his grace" (Ephesians 1:7).
Original sin - What is it?
The sin nature - What is it?
How can I have victory in overcoming sin?
Spiritual death - what is it?
How do I receive forgiveness from God?
Truth about Sin