quietly summarize v201
scalar max_ceb=r(max)

keep v011 b3* bord*
rename b*_0* b*_*

* bord_1 is the birth order of the most recent birth
* the first birth will be the one for which bord_1=1 or bord_2=1 or bord3=1, etc
* the second birth will be the one for which bord_1=2 or bord_2=2 or bord3=2, etc

local lj=1
quietly while `lj'<=max_ceb {
gen b3ordered_`lj'=.

  local li=1
  while `li'<=max_ceb {
  replace b3ordered_`lj'=b3_`li' if bord_`li'==`lj'
  local li=`li'+1 
  }

local lj=`lj'+1
}

summarize b3_*
summarize b3ordered_*