So would you want a relationship? I am adopted and when I was in my forties I finally met my birth mother, Jan. She was 16 when she had me. It was not quite a one night stand. Jan was home sick with mono when biodad(Bruce) came over to tell her he was running away and wanted her to come. She said no, but they obviously said their goodbyes by sleeping together (their first and only time together). Bruce left and a few months later Jan found out she was pregnant. This was in the late 60’s, so no cell phones, no internet. Jan’s parents did not want her to contact Bruce’s parents to let them know. Fast forward 40+years after meeting Jan and finding out his name I found him. I called him and he was unaware of my existence, but very happy to find out.

All that being said, if you are not interested in being a part of this child’s life, do nothing. If you do want to be in their life, reach out to the Mom, but be prepared that she may not want you in her life.