This Sunday -- Mother's Day, ironically enough -- marks the 50th anniversary of an invention that gave women greater power to choose if and when they wanted to become a mom.

The approval of the birth-control pill in 1960 ushered in an era that many argue transformed the lives of women, giving birth to the sexual revolution, spawning the women's liberation movement and changing the face of the once male-dominated workforce.

The pill also changed forever the relationship between the sexes by giving females ultimate control over avoiding an unwanted pregnancy. And for the first time, popping that little tablet each day meant women could engage in sexual pleasure on a whim without the unromantic foreplay of condoms, diaphragm or other contraceptive contraptions.

Among the first generation of women to take the oral contraceptive, Abby Lippman recalls that she and her 20-something friends living in New York couldn't wait to get on the pill, which was approved for widespread use by the U.S. Food and Drug Administration in 1960.

"The pill seemed wonderful," says Lippman, an epidemiologist at McGill University in Montreal who specializes in women's health. At the time, abortion was illegal, and those obtained clandestinely through doctors willing to perform the procedure were usually expensive, dangerous or both.

While the U.S. has given the advent of the oral contraceptive a definitive anniversary date, the story of the blockbuster pharmaceutical in Canada is a little more difficult to pin down.

The pill had been available with a doctor's prescription to Canadian women as early as 1957, but only for "menstrual irregularities" -- never (at least officially) as a means of avoiding conception. At the time, advertising or selling contraceptives could result in a fine or jail time, unless it could be shown to be in the "public good."

In fact, the pill was illegal in Canada until 1969, when a Trudeau government bill that also legalized "therapeutic" abortions and homosexual acts between consenting adults was passed by Parliament.

The whole notion of a medication that could prevent pregnancy caused a furor. Some religious groups -- chief among them the Catholic Church -- and other opponents contended that the pill should be banned outright or at the least restricted to married women as a means of limiting the number of children. Prescribing the oral contraceptive to young single females would lead to a breakdown in morality and rampant sexual promiscuity, they argued.

One Montreal psychiatrist concluded in 1965 that the pill made women unfeminine and that some patients complained "they were no longer interested in their homes, in their children, even in their husbands."

A Toronto Liberal MP, who vocally opposed his party's bid to legalize contraception, proclaimed in 1966 that use of the pill was already emptying out hospital maternity wards.

"What we need is not birth-control, but self-control," Ralph Cowan told the now-defunct Weekend Magazine. "If things go on this way, in 20 years we'll have so many old people there won't be enough young people to pay for their welfare programs."

Christabelle Sethna, an associate professor in the Institute of Women's Studies at the University of Ottawa, says at last some of the controversy arose because many people -- including some doctors -- did not understand how the pill prevented pregnancy.

"Some doctors felt it was an abortifactant, that it provoked abortion," she explains. "They were confused how it worked because it was so new."

While Sethna agrees that the pill created a huge paradigm shift in male-female sexual relations, she argues against the idea, in Canada at least, that oral contraception led to women's lib and the rush of females into post-secondary education and the job market.

"It didn't and that's the mistake," says Sethna, who is writing a book on the history of the pill in Canada. "A lot of people felt that the pill was responsible for the sexual revolution. But when you look at the time period, women were already starting to enter the workforce and women were already having sexual relations outside marriage."

"The pill coming on the scene sort of accelerated all of that."

What the pill did do is alter the responsibility for avoiding pregnancy, thereby creating not only a massive sea change for women, but one that also affected men.

"Before the pill, the most popular methods of birth-control were male-dependent," says Sethna, noting that other than abstaining from sex, women were reliant on male partners to use a condom or "to withdraw."

"So then this pill comes on the scene and it's female-dependent, it's utterly female dependent. So that in and of itself is revolutionary ... By making women virtually completely responsible for contraception, it's made men's role in conception invisible."

"It has changed men's lives tremendously."

Lippman of McGill, who ended up ditching that first-generation pill just months after starting it because of side-effects, agrees the oral contraceptive empowered women to protect themselves from unwanted pregnancy.

"But was it revolutionary? When I look at how young women now still need to use condoms to have safer sex, how there's still a growing frequency of chlamydia and other sexually transmitted infections ... it's hard to see this as the greatest thing that ever happened to women, when women's sexual and reproductive health is still at risk in so many ways."

"The pill is not the only thing women need to have good sexual and reproductive health. It's a necessary but not sufficient ingredient in a package of things that women need."