Both St Thomas and St Augustine (and who knows how many other saints) say that Original Sin is due to ADAM’S sin alone.
Who made what they say dogmatic truth? St. Thomas taught against the Immaculate Conception, but he was obviously wrong there.
Adam is blamed insofar that he allowed Eve to be navigated by her own faculties as she was left alone, rather than leading her, thus she first sinned by trusting in Satan (the Serpent) over God, because she wanted to be like God with knowledge. Adam is, also, blamed because he's the human father of humanity. Eve was created from Adam's rib by God, therefore, Adam had authority over her, and he was, ultimately, responsible for her actions. However, Eve was the first sinner because her action met all conditions required for sin. All of nature fell because of her, and this fall transcended to Adam, thus making him more susceptible to being corrupted by her in the Garden. Ecclesiasticus tells us that the beginning of sin came from Eve, and we all die because of her. Again, the reason is because Eve was the first person to meet all conditions of sin: 1) Its subject matter must be grave. 2) It must be committed with full knowledge (and awareness) of the sinful action and the gravity of the offense. 3) It must be committed with deliberate and complete consent.
Adam's lapse in leadership didn't meet all conditions required of sin, but he, ultimately, gets the blame by some Church doctors because he's the human father of humanity and he had authority over Eve. Of course, Adam had to, also, sin, which he did by eating of the apple, but it was Eve who sinned first and seduced Adam to eat of it.
The fall of nature and death transcended through Eve to Adam.
The salvation of man transcended through Blessed Mary to Jesus Christ.
Eve chose to sin, and Adam followed her example rather than remaining a humble creature before God and trusting in Him.
Blessed Mary chose to reject sin which allowed herself to continue to be an immaculate vessel for the Creator of Life - the Logos - Whose human nature, subsequently, chose to reject sin and fulfill the Divine plan of His holy sacrifice so we might have eternal life.
In short, if Eve hadn't sinned first, Adam wouldn't have sinned and there would be no fall of nature. If the Immaculate Conception hadn't chosen to reject sin in her life, and had she rejected the Lord's plan for her to be a vessel for Our Redeemer, the Word would not have become flesh and dwelt among us, and we would have no salvation.
Don’t ignore them in your quest to correct women.