Suse - thanks for the tip about the lavender oil. Is it just if its used directly on baby boys' skin?
As far as I am aware, Willow, yes, it's only thought to potentially be an issue if directly absorbed by the skin. Oil burners/diffusers should be fine. I wish that I had a copy of the material that I read so that I could reference it properly, (it was a reference text on the chemical structure of essential oils), but from memory it noted that lavender is oestrogenic but that no specific research could be found to indicate how much would need to be absorbed in order to have an effect on hormone levels (and possibly on testicular development) in infant boys. TBH it's probably unlikely to be an issue because only very small and highly diluted quantities can be used on a baby's skin without causing irritation (and the concentrations in most commercial preparations are tiny!), but I believe that some aromatherapists are advising caution until further research is done. However, lavender has been used in baby care products for quite a long time, which does suggest that it is unlikely to cause any ill effect on boys!