In Heller, Scalia's opinion is a textbook analysis: text, prior history, precedent, etc. The core of the individual right is self-defense, and being able to defend the family and home. The dissenters disagree about history, and say it should be left to the legislative branch (as it had been for 200 and some-odd years).
This sort of rode on Griswold. In that case, CT was the only state still to have a ban on prescription contraceptives. The idea is that the Bill of Rights creates zones of privacy: 1A association, 3A not quartering soldiers, 4A search and seizure, 5A self-incrimination, and 9A non-enumerated rights. Still, the court went beyond the text of the Bill of Rights and finds a new fundamental right, which kind of took on a life of its own. Interesting footnote: Douglass had just started his 4th marriage when this case came out-- possibly the discussion of the rights of married couples to govern their own affairs (as a right pre-existing the constitution, in an interesting parallel with Heller) was influenced by his relationship with his new bride, a recent law grad who was working in his office.
Anyway, Roe finds a fundamental right to an abortion if the fetus is not viable: it's subject to strict scrutiny, so nearly any attempt to reign it in will be struck down.