@OldCrone,
'If you took the results of tests from one baby at random, you would not be able to tell from its preferences whether it was a boy or a girl.
For example, in this study, the results of one test (whether a child had a preference for looking at a face or a mobile), the results for boys were 25.0% face, 43.2% mobile and 31.8% no preference. For girls 36.2% face, 17.2% mobile and 46.6% no preference.
So if a baby preferred looking at a mobile, it is more likely to be a boy than a girl, but a fair number of girls also had this preference. If a baby preferred to look at a face or had no preference, it is more likely to be a girl, but you could not be anywhere near certain of this.
This was also a very small study, with results from only 102 babies (44 boys, 58 girls).'
This study was not designed to be a new way of sexing babies. (If it were, I agree, it would be a dismal failure, with the tried and tested method of looking at external genitalia proving far more effective!).
It was designed to see if there was an overall preference difference in population level between male and female babies' preferences, and it found that there was.
Yes, it was a relatively small sample. However a chi squared test was done and the result was found to be significant:
'Table 1 shows the number of babies that fell into each of the 3 categories. A x2 test demonstrated that there was a significant association between sex and stimulus preference
( x2 5 8.3, df. 5 2, p 5 0.016). An analysis of adjusted residuals demonstrated that the significant result is due to more of the male babies, and fewer of the female babies, having a preference for the mobile than would be predicted. In other words, male babies tend to
prefer the mobile, whereas female babies either have no preference or prefer the real face'
It also backs up the macaque study.
Taken together, I feel that this is evidence (not proof) that some gendered behaviour is biological.