Illegitimate children this is the situation:
a children is born from fornication years ago when the couple were young, years passed the guy married. the women gave the child for adoption. Now the women brings up the child (who is an adult now) to the guy who is happily married. What does the Buddhist texts or teachings say about the illegitimate children born from fornication?,
Is there anything  that mentions this?
Buddhism concerns itself with the behaviour of people rather than birth status. Refer to MN 98.
In other words, an ethical person who was an illegitimate child is regarded to be superior or happier than an unethical person who was a legitimate child.