I was born in 1979. All of my cousins are older than me and quite a few of them were adopted, so early to mid 70s. A few of them made contact with their adoptive parents with varying degrees of success.
One of them is only a year older than me. She had always known that she was adopted (her older brother was too, but they weren't biological brother and sister) and in her twenties searched for her parents. I'm not 100% sure of what happened with her birth father, whether she knows who he is or not, but she met her birth mother and they got on really well.
She got married about ten years ago, by which time her adoptive father had passed away, so her adoptive mother and her biological mother both walked her down the aisle which was lovely.
On a sadder note though, a friend of mine the same age as me traced her biological mother when she was in her twenties, but her mother didn't want to know. She had got married and had four other children, but neither her husband or her children knew about her and she didn't want them finding out.
My friend was really upset over it. Her biological father's name is on her birth cert, so she knows who is he is and where he lived (well, at that time anyway) but after being rejected by her biological mother she didn't try and trace her father in case the same thing happened again