Clearly biased: Maternal recall of asthma in the family

I have heard it many times on congresses and there seems now even a meta-analysis of a possible preferential maternal transmission of asthma to children. And of course, there are important biological question behind (imprinting? maternal antibody transfer?) but unfortunately this is nothing else than a spurious effect.
The author’s view is well taken that we did the first modern family study 1992 but unfortunately they do not make any distinction between the person who has been interviewed for the family history.

In our experience 90% of the family interviews are done with mothers – and of course they recall their own childhood better than that of their husband.

This effect is modest (OR 3.04 versus 2.44), but statistically significant. This demonstrates that non-genetic in utero and/or post-natal factors may play a significant role in the transmission of asthma susceptibility.

So while I agree on the modest affect, I can’t agree on the conclusion. Even if there would a true difference between maternal and paternal risks the conclusion of non-genetic effects may be wrong, sorry, PLoS ONE seems to crowdsource reviews now…