/summa/TP/TPII/TP_Q34:
We must now consider the perfection of the child conceived: and concerning this there are four points of inquiry:
(1) Whether Christ was sanctified by grace in the first instant of His conception?
(2) Whether in that same instant He had the use of free-will?
(3) Whether in that same instant He could merit?
(4) Whether in that same instant He was a perfect comprehensor?