Chance News 36

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Quotation

Forsooth

Sex and Cereal

A sure way to obtain column inches in the media for biological/medical research is to study sex selection and relate it to something unexpected. In this instance, 740 pregnant women were asked to fill out a survey which dealt with their physical characteristics, habits and most of all, daily dietary intakes.

The Independent: "Big breakfast is most important meal -- if you want a baby boy."

Reuters: "Skipping breakfast may mean your baby is a girl."

New Scientist: "Breakfast cereals boost chances of conceiving boys."

CNN.com: "Study shows bananas make baby boys."

New York Times: "Boy or Girl? The Answer May Depend on Mom's Eating Habits."

Choosing a provocative title doesn't hurt "You are what your mother eats: evidence for maternal preconception diet influencing foetal sex in humans." According to the lead author, "If you want a boy, eat a healthy diet with a high calorie intake, including breakfast." From the New Scientist, "When the researchers divided the women into groups with high, medium and low intake of energy, they found that 56% of women in the high-energy group had boys, compared with 45% in [the] lowest group." Further, "Cereal intake had a bigger effect," producing 59% boys when eating one or more bowlfuls per day, "compared with only 43% who bore boys in the group eating less than a bowlful per week." The researcher tested many foods and found only cereal "significantly associated with infant sex."

Discussion

1. In [1] is a wiki which looks at a different study-on mice-which also claims that nutrition affects the percentages of males and females. Which of the two is an experimental study and which is an observational study?

2. The current study was done in England and of the 740 mothers-to-be, 301 (approximately 40%) said they currently were smokers. Why would this fact cast doubt on the conclusions being applied to the United States?

3. Eating cereal for breakfast is a very American habit, duplicated in few countries; even those other countries, such as England where cereal is eaten for breakfast, have nowhere near the selection possibilities obtainable in the United States. Many industrialized countries eat little or no breakfast at all. What then should the male/female ratio be for these countries?

4. It is often said that many cereals are really candies in disguise. If so, should the mother-to-be "cut to the chase" and just have a candy bar for breakfast? If not, why not?

5. Instead of the customary .05 level, the researchers chose a p-value < 01 for determining statistical significance. Why did they lower the p-value?

6. The researchers keep referring to a "bowl of cereal." Why is this an exceedingly inexact measure?

Submitted by Paul Alper
















"Cereals seem to be one of the key food groups."

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