Comings and goings of couples adopting daughter (5)
I believe the answer is:
tides
'comings and goings' is the definition.
(tides come in and go out)
'couples adopting daughter' is the wordplay.
'couples' becomes 'ties' (I've seen this in other clues).
'adopting' is an insertion indicator.
'daughter' becomes 'd' (genealogical abbreviation).
'ties' placed around 'd' is 'TIDES'.
'of' is the link.
(Other definitions for tides that I've seen before include "Periodic changes in sea levels" , "Lunar ocean movements" , "Sited (anag.)" , "Sea movements caused by moon" , "Rises and falls, nautically" .)