Binary trait random regression

Hello all,

I have a question regarding the wisdom of fitting a random regression
model of fecundity (scored as 0 or 1) in a human data set where
fecundity has been scored annually for several hundred women for each
year of their life (from 16-50 I think). I have fitted the two models
below and get apparently sensible results from the second of these in
which I wanted to test for a genotype by age interaction.

fec !binary ~ mu fixedFX !r leg(ageS,0).ANIMAL leg(ageS,0).ide(ANIMAL)

fec !binary ~ mu fixedFX !r leg(ageS,1).ANIMAL leg(ageS,1).ide(ANIMAL

However, I'm also aware that there are issues relating to the use of
generalised animal models, and was wondering if anyone had views on
whether this was valid? Also, if the approach is not inherently wrong,
is there any way to statistically compare these models if, as I
understand, the likelihoods should not be used for model comparison.

Best wishes,

Alastair

--
Alastair J Wilson
NERC Research Fellow
Alastair.Wilson_at_ed.ac.uk
http://wildevolution.biology.ed.ac.uk/index.html
http://wildevolution.biology.ed.ac.uk/awilson/index.html
tel. 0131 6513608
Institute of Evolutionary Biology
School of Biological Sciences
The University of Edinburgh
Ashworth Laboratories
The King's Buildings
West Mains Road
Edinburgh EH9 3JT, UK