Dear Rabbi Kornfeld
Why, after a long discussion of Hilchos Kria, and before a long discussion of Hilchos Havraah, does the Gemara put in a halacha that an ovel should not hold a child on his lap?
Gershon
Possibly the reason is because the previous Briasa stated that we do tear Keria on the garment of a child who is underage "in order to increase suffering and crying." The Gemara follows that with the prohibition of taking a child in one's lap, since it is based on a similar logic: that we are not supposed to decrease the feeling of mourning of the Avel. Consequently we are to refrain from acts that would increase happinesss and comfort like cuddling children.
(Sorry for the delay in our response)
-Mordecai