Also, in the S1 finale, Gold tells Emma about the ‘True Love’ potion. He says when he created the Dark Curse, he added a single drop as a ‘safety valve’.
I wouldn’t be surprised if he added many ‘safety valves’ to the curse.
Names are important to Rumplestiltskin.
When Gold discussed the adoption with Regina in the pilot (after he got his memory back), he mentioned the fact that she named him Henry- asked her how she picked the name..which we know was her father’s name.
I think it may be a combination of a safety valve in the Dark Curse and the name Henry that allowed Gold to ‘procure’ him for adoption by Regina- even tho Gold/Rumple didn’t have his memories at the time of the adoption.