A discussion on what one mean by clear difference would be relevant here. There are studies that talk about various differences between the sexes. But in those studies difference is expressed in terms of average difference of statistical distributions of certain measurements. Frankly, I don't understand how to interpret them. I wonder when I see these results, do my opinion about them also gets normally distributed? Or do I need to select a certain interval and view it as true and the rest false? But the practical application of statistical analysis is not only to measure the variability but also to minimize it by tweaking the variables. Hence, it can be also viewed as a measure of success or failure of our optimization.
Considering all these complications, I would prefer having binary opinion. This of course requires;
- binary results for any experimentation
- no room for optimization
And I have found in the case of parenting this could be obtained. I have already blogged about couple of studies on this:
1. Mother's positive influence on daughter. Mother' no influence on son. Father's influence on both son and daughter.
2. Mother's negative influence on daughter.
There is a new study that further supports the second point.
the participants listened to 30-second audio recordings of remarks from their mother. Some comments were praising, some were critical and others were neutral in content. The comments were previously recorded over the telephone with the permission of the mothers. The participants were also asked to rate their mood on a scale from one to five after hearing the different kinds of remarks.
Despite being healthy and reporting similar conscious reactions to the recorded comments, the formerly depressed showed different activity in their brains, compared to those who had never been depressed. "When we asked them how they felt after being criticized, they responded in the same way as the controls did," said Hooley. "But when we looked at the brain scans, the patterns of activation were quite different. So this is happening under the radar of awareness."
The results of those studies are captured in the following tables.
Thus we can say that father is a complete parent as he can influence both his son and daughter but mother is just half as she can influence only her daughter.
Now what about the combined influence of parents? Especially when one is positive and the other negative. There would be influence nevertheless but will it be positive or negative? It is very clear that there can't be any combined influence on son. What about the daughter? I haven't come across any studies on them. I can't apply logical AND or OR function here. We have to understand here, positive or negative they just complete the influence and hence true. To understand the combined influence we need to understand the underlying biological basis for this.
The first clue could be found in mother's non-influence on her son. The only reason why a mother can't influence her son could be the difference in sex chromosomes or SRY region of Y-chromosome in particular. Therefore, everything boils down to sex chromosomes. And this in turn gives further clue why a father can influence both his son and daughter. Now our interest is what happens when one of the parents have positive and the other negative influence. A simple model is mother influences thro' her X-chromosome and father thro' his. It's all Epigenetics (Epi=Beyond; Genetics).
We know that a defective gene expression is suppressed by a corresponding normal gene. This we can view as negative getting nullified by positive. Taking this concept further we can say that negative epigenetic behaviour is suppressed by positive epigenetic behaviour. Hence, a daughter can have positive outlook even with just one parent being positive about her.