Hello,

Just another suggestion !!

Check the Gary King's web page (http://gking.harvard.edu), specifically the software link at the botton of the page (http://gking.harvard.edu/stats.shtml).

He worked in the implementation of the rare events logistic regression methods for Stata and GAUSS statistical packages suggested in King and Zeng (1999a,b) for generating approximately unbiased and lower-variance estimates of logit coefficients and their variance-covariance matrix by correcting for small samples and rare events.

I've been checking the Stata command and you can obtain the robust estandart estimation and it may be an aproximation for your X-seccional data

-- Pere-Joan Ventura