The singer says at first he didn't understand why some people saw the lyrics as "rapey".
But he later realised that "there are men who use the same language when taking advantage of a woman".
Blurred Lines was criticised by some who claimed the lyrics referred to non-consensual sex.
It was banned at several universities and an advert featuring the song and models from the video was also banned from daytime TV in 2013.
In an interview with GQ magazine, Pharrell, 46, said he was "born in a different era" and some things that were allowed at the time would "never fly today".
Giving examples he referenced adverts that "objectify women" and "song content".
"Some of my old songs, I would never write or sing today.
"I get embarrassed by some of that stuff. It just took a lot of time and growth to get to that place."
He said Blurred Lines was the turning point for him but he admitted that at first he "didn't get" why the song received such a backlash by some.
The song - which was a collaboration with Robin Thicke - includes lines such as "I hate these blurred lines, I know you want it" and "Must wanna get nasty".