Mitt Romney was pro-abortion before ROE v Wade, the left fought for abortion and got it in 1973, it is unlikely the Court decision would have been simply pulled out of the air and dumped on America without the political war of the pro-abortion forces, like the Romneys.
Romney was born March 12, 1947. He was about 26 yrs old when the Supreme Court made this ruling. At that time he was working for the Boston Consulting Group as a managment consultant.
Sorry, you can't blame this on him. He wasn't into politics for another ~20 years.