In the early chapters of the book of Genesis it uses “Adam” to refer to ‘humanity’: When humankind [Adam] began to multiply on the face of the earth (NET Gen. 6.1). This then is what people are: Adamites. Acts 17.26 records Paul address to Greek philosophers at Athens where he claims this same idea of the unity of all people: and he made from one man every nation of mankind to live on all the face of the earth (ESV).
Sometimes a person will say they never asked to be born or that they had nothing to do with Adam’s sin, and that God should deal with them apart from other’s failures (Adam’s). But this is not the case in point. The bible teaches that we participated with Adam in the fall in Rom. 5.12: So then, just as sin entered the world through one man and death through sin, and so death spread to all people because all sinned. The verb “sinned” is aorist in the Koine Greek indicating point-in-time action. So all of humanity at the same time participated with Adam in his fall. A similar concept is found in Heb. 7.9-10: And it could be said that Levi himself, who receives tithes, paid a tithe through Abraham. For he was still in his ancestor Abraham’s body when Melchizedek met him. The writer of Hebrews affirms action of Levi before he was born: paying tithes! This is how we are to count our situation now since the bible clearly presents humanities’ predicament as prior action while either genetically participating, or as the ancestor (Adam) as representative for the whole. In theology this study is called the Headship of Adam with the two major views: natural (genetic) and Federal (representative).
My view is that the sin was actual and not representative. To me this takes Rom. 5.12 normally which mentions nothing of putting forth a representative but attributes the fall to everyone. This view is also harmonious with the concept of Levi paying tithes before he was born. The remedy of course is the second and last “Adam” (Jesus): So also it is written, “The first man, Adam, became a living person”; the last Adam became a life-giving spirit. However, the spiritual did not come first, but the natural, and then the spiritual. The first man is from the earth, made of dust; the second man is from heaven. Like the one made of dust, so too are those made of dust, and like the one from heaven, so too those who are heavenly. And just as we have borne the image of the man of dust, let us also bear the image of the man of heaven (NET 1 Cor. 15.45-49).