Health effects of inbreeding 
Inbreeding increases the probability that deleterious recessive alleles will come together in homozygous combination: it increases the proportion of such births in the population.

What is the ratio of deleterious recessive homozygotes
    in an inbred versus a non-inbred population?

If F = 0 (population is not inbred) then
        q2exp / q2obs  = 1

if F > 0 (population is inbred) & q << 1  then
      q2exp / q2obs  =  (q2 + Fpq) / q2   (q2 + Fq) / q2   =  (q + F) / q    F/q

Ex.: if q = 10-4   &  F = 0.01   then F/q = 102 = 100

   i.e., a very small degree of inbreeding results in a 100-fold increase in the proportion of deleterious homozygotes

Text material © 2007 by Steven M. Carr