clear
set obs 200
generate x1 = runiform(-3,3)
generate x2 = rlogistic() < (x1)
logit x2 x1
generate y = rlogistic() < (x1 + x2)

logit y x1 x2

gsem (y <- x1 x2, logit) (x2 <- x1, logit)
nlcom _b[y:x2]*_b[x2:x1]