But you can also thank a woman many people have never heard of. Her name is Estelle Griswold.

In the early 1960s, birth control options were growing. Condoms had been around for a long time, but things like contraceptive foams, IUDs and early types of birth-control pills were still relatively new. (The U.S. Food and Drug Administration had approved the first birth-control pill in 1960.) These forms of contraception existed, but in some parts of the country there was a problem: They could be very hard to get.  

Powerful religious lobbies didn't want couples - even married ones - to have access to birth control. They used their influence to make it next to impossible for people to get birth control in some states.

That changed because of events in one New England state. In Connecticut, an 1879 law banned the sale of contraceptives. (The law had been proposed by state Sen. P.T. Barnum, who had entered politics following his national fame as a circus showman.) Not only did the law ban the sale of birth control, it also prohibited doctors from counseling couples about it. Although only sporadically enforced, the measure was enough of a nuisance that advocates of women's rights knew that it had to go.

They first tried lobbying the legislature to repeal the antiquated law. But the state's powerful Catholic hierarchy put the kibosh on those efforts, so Griswold, executive director of the Planned Parenthood League of Connecticut, joined forces with Dr. Charles Lee Buxton, chairman of the Obstetrics Department at Yale Medical School, to try a different strategy: They decided to test the law in court.

To create a test case, the two opened a clinic in New Haven to dispense information about birth control. The clinic didn't handle any actual birth control devices; it merely dispensed information about options. Nine days after it opened, police raided the clinic and arrested Griswold and Buxton - which was just what they wanted.

Connecticut courts were not sympathetic to Griswold's and Buxton's arguments, but the U.S. Supreme Court felt differently. On June 7, 1965, the high court struck down Connecticut's anti-birth control statute. Ruling 7-2 in Griswold v. Connecticut, the court majority, led by Justice William O. Douglas, cited a "zone of privacy created by several fundamental constitutional guarantees."

Douglas went on to write, "Would we allow the police to search the sacred precincts of marital bedrooms for telltale signs of the use of contraceptives? The very idea is repulsive to the notions of privacy surrounding the marriage relationship. We deal with a right of privacy older than the Bill of Rights...."  

That "zone of privacy" resurfaced over the years. It was cited in later cases that struck down laws barring use of birth control by unmarried people. It appeared in 1973's Roe v. Wade, the abortion-rights case. It returned in 2003 when the Supreme Court struck down a Texas law criminalizing consensual same-sex relationships in Lawrence v. Texas.

I often give talks about church-state issues to local groups and at conferences, and every time I bring up the Griswold case, I notice a generational divide: The younger people are startled to learn how bad things once were. The older folks, who lived through it, merely nod their heads knowingly.

The older crowd has some wisdom for us on this matter. Their experiences remind us that just about every advance of human rights and individual freedom concerning sexuality was accompanied by a fight against entrenched opposition from repressive religious groups that were certain they knew what was best for everyone.

Their grip was broken, thanks to brave people like Estelle Griswold. The theocrats among us are still smarting from that loss of power. They would like to get it back, and they constantly plot for that.

Don't think they can't succeed. Remember, it was just last year that the Supreme Court, in its absurd Hobby Lobby ruling, declared that some corporations can exercise religion and have the right to deny their employees access to birth control in health-care plans.

Estelle Griswold died in 1981. This weekend, take a moment to reflect on what she and other advocates did for us. But do more than reflect on Griswold's legacy- vow to defend it.