Or you could just read the ruling to see how it is justified...
You know, some of us liked the Constitution just fine before Warren, Brennan, and Marshall "interpreted" it, and some of us think the text of the Constitution matters more than court opinions.
It does not specifacally say that women have the right to get an abortion. The framers wouldn't have even been able to fathom such a procedure as an abortion. However, it is implied that every individual has the right to privacy and that includes that individuals own body. And where exactly does it say that a fetus is counted as a whole person? The framers counted African-Americans as three-fifths of a person when taking a census. How much would a fetus be counted for? Maybe it would depend on that fetuses color of skin.
If this is what the courts have found, why don't I have the right to shoot heroin? Hey, its my body. But the judges have an ideology that doesn't include legalizing heroin, so they don't apply their standard consistently. They only apply it where their ideology says its fine.