clear

cd e:\chililabdata\data
use individual
sort individid 
save, replace
use birth
sort individid
duplicates drop individid, force
merge 1:1 individid using individual, keepusing(gender motherid)
rename gender sex
rename individid childid
rename motherid individid
gen socialgpid = substr(observeid,1,9)
replace bth_date= bth_date/86400000
format bth_date %td
gen year = year( bth_date)
gen h = halfyear(bth_date)
gen round = yh(year,h)-89
tostring round, generate(rounds)
replace rounds = "0" + rounds if strlen(rounds) ==1
gen socialkey = socialgpid+  rounds
gen individkey = individid+  rounds
drop  eventid observeid individidGuid _merge h  
drop if round < 0
save rBirths, replace