Australasian Science: Australia's authority on science since 1938

Nuns Would Benefit from the Pill

By Magdeline Lum

Interesting experiments and quirky research findings.

A paper published in The Lancet declares that if “the Catholic church could make the oral contraceptive pill freely available to all its nuns, it would reduce the risk of those accursed pests, cancer of the breast, ovary, and uterus, and give nuns’ plight the recognition it deserves”.

A comment piece titled “The Plight of Nuns: Hazards of Nulliparity” cites research that directly links the number of menstrual cycles a woman goes through to her risk of cancer. The younger the arrival of periods or a late onset of menopause are factors linked to a higher cancer risk. Nuns, being childless, generally have no breaks from their periods. Not having children is another risk factor for developing cancer because pregnancy and breastfeeding reduce the number of ovulatory cycles a woman has. The more ovulatory cycles, the higher the risk of cancer.

In the first half of the 20th century scientists who studied 31,568 nuns in the United States found that the death rates from breast, ovarian and uterine cancer among nuns were higher than any other women their age. In 1970, a formal recognition was made that it was the lack of childbearing among nuns that raised their breast cancer risk.

Dr Kara Britt and Professor Roger Short, authors of the commentary, state that the oral contraceptive has been shown to reduce the incidence of uterine and ovarian cancer rates. There are also now forms of contraceptive pills that can suppress menstruation for months or altogether.

They also highlight that when Pope Paul VI condemned all forms of contraception except abstinence in the Humanae Vitae in 1968, nuns were not included. The document also states that “the Church in no way regards as unlawful therapeutic means considered necessary to cure organic diseases, even though they also have a contraceptive effect”.

It is on this tenet and evidence cited that the authors conclude that the Catholic church should make the contraceptive pill freely available to nuns.

Females Choose Sexier Friends to Avoid Pushy Males
Scientists have observed a strategy used by female fish to avoid unwanted male attention. It is remarkably simple: they choose more attractive female companions to spend time with to reduce harassment from males.

Researchers from the Universities of Exeter and Copenhagen focused on the Trinidadian guppy, the original source of aquarium species known to fish-keepers worldwide. Male guppies are renowned for their frequent overtures and at times aggressiveness towards potential mates. This can lead to females being prevented from finding food in their escapes from overly amorous males.

Descendants from guppies living in the Aripo River in Trinidad were used in the study. Since female guppies are receptive to mating for only a few days each month, at which time they emit a sexual pheromone to attract males, the scientists divided them into two groups – one made up of females receptive to mating and the other made up of females that were not. The scientists then monitored the amount of time that both receptive and non-receptive females spent with one another.

They found that non-receptive females spent significantly more time with receptive females (which are more sexually attractive) and garnered less attention from males.

To further test this, non-receptive females were given the choice of swimming in water in which receptive females had swum in and water that non-receptive females had spent time in. Non-receptive females chose water that had housed receptive females, showing that they detected chemical cues left by their more attractive counterparts.

Lead researcher Dr Safi Darden of the University of Exeter said: “It is now becoming apparent that males of some species choose to associate with relatively less attractive males to increase their chances of mating. We wanted to see if females also chose their same-sex companions based on attractiveness, but in this case, to reduce unwanted attention.

“Our results support the idea that social structure can develop around relative attractiveness and mating strategies. Although we focused our study on one species of fish, I would expect that this strategy would be seen in other species where females face similar levels of unwanted sexual attention from males.”