Guy friends draw parallels between adopting daughter and son (9)

'guy friends' is the definition.
'compadres' can be an answer for 'friends' (I've seen this before). I am not certain of the 'guy' bit.

'draw parallels between adopting daughter and son' is the wordplay.
'draw parallels between' becomes 'compare' (I can't justify this - if you can you should give a lot more credence to this answer).
'adopting' indicates putting letters inside (inserted letters are taken on or adopted).
'daughter' becomes 'd' (genealogical abbreviation).
'and' says to put letters next to each other.
'son' becomes 's' (genealogical abbreviation for son).
'compare' placed around 'd' is 'compadre'.
'compadre'+'s'='COMPADRES'

Can you help me to learn more?