In the early '60s, she became one of the first women in New Zealand to take the contraceptive pill. At the time, it was only available to married women.
But it wasn't until 1969, after she separated from her husband and began working for the student health service at Victoria University, that she began to question the state of things.
Abortion had recently been legalised in Australia and young women would regularly come to the clinic pleading for Sparrow to help them. At first she turned them away, as was the law, but soon Sparrow changed her mind and began booking airfares and helping women secure safe abortions overseas. She also introduced the morning-after pill and was one of the first doctors to prescribe it in New Zealand.
Two years later, she trained with Family Planning and began campaigning for safe, legal abortion in New Zealand. She became the president of the Abortion Law Reform Association of New Zealand - a role she would hold for more than 30 years.
In 1977, Sparrow was devastated when Parliament ignored her lobbying and passed the Contraception, Sterilisation and Abortion Act, which states abortion is a crime in New Zealand, unless two consultants agree it is necessary for a mother's mental or physical health.
The controversial law still stands today and remains one of the great frustrations of Sparrow's life. But it hasn't stopped Sparrow's campaign for progress.
In 1980, she began performing abortions at the newly opened Parkview Clinic at Wellington Hospital. Navigating angry protesters in the carpark became a regular part of her working week, while pro-life campaigners targeted Sparrow's home, telling her neighbours they lived next door to a murderer.
While the protesters didn't deter Sparrow, the clinic itself did when it declared all doctors must become certifying consultants. Sparrow couldn't bring herself to endorse a system she had actively protested and instead gave up her job at the clinic.
Still, she continued to fight for what she believed in and in 2001, together with four other doctors, she began importing the French abortion pill mifepristone into New Zealand, giving New Zealand women access to non-surgical abortions.
Today, aged 83, Sparrow still hopes to see the day abortion is legalised in New Zealand - as it was recently in Ireland.
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