  We consider a recently-proposed alternative explanation of the CV period gap
in terms of a revised mass-radius relation for the lower main sequence. We show
that no such thermal-equilibrium relation is likely to produce a true gap.
Using population synthesis techniques we calculate a model population that
obeys the claimed equilibrium mass-radius relation. A theoretical period
histogram obtained from this population shows two prominent period spikes
rather than a gap. We consider also recent arguments suggesting that the period
gap itself may not be real. We argue that, far from demonstrating a weakness of
the interrupted-braking picture, the fact that most CV subtypes prefer one side
of the gap or the other is actually an expected consequence of it.
