It is a very serious problem. All religions are a pest to mankind. Religion is the opium of people. Religion has done great harm to humanity during its history.
Let’s take an example. Religion pretended that a child born out of wedlock does not have any rights regarding the inheritance of his father’s wealth, because the child would be illegitimate since the father of such a child is not registered in any document as being the child’s father.
In ancient times, during the time of patriarch Abraham, children made by the patriarch with his slaves were legitimate, but only if one of his legitimate wives accepted to have the slave giving birth on her knees. The slave was in fact the wife’s slave. Abraham could sleep with the slave only with his wife acceptance and his wife must have accepted the ritual of birth on her knees. All these things were equivalent to an adoption made by the wife.
Abraham had only one wife, his stepsister from the same father, Sara. He had one son with Sara, named Isaac. Sara had an Egyptian slave, Agar, whom Abraham had a son, whose name was Ishmael. Isaac, the son of Abraham and Sara, married Rebecca, his primary cousin, the daughter of his mother’s brother.
Isaac had two children with Rebecca. The younger one, Jacob, married two sisters, also his primary cousins, Lea and Rachel. With them and with their slaves, Jacob had twelve children (the twelve patriarchs) representing the twelve tribes of Israel.
Another case, this time from the real world and not a biblical legend, is of the king William the Conqueror. His father was a great noble, very rich and influential but he had no children with his legitimate wife. He slept with William the Conqueror’s mother and the child has born. In his will is written that William is his natural son, his only son.
William the Conqueror had numerous wars because neither the nobles nor the clergy wanted to accept that he had any rights. He got married with Matilda, daughter of a rich and influential noble like his father was. He founded a kingdom. Because many regions belonged alternatively to France and England, William the Conqueror is claimed by both, the British and the French.
What is noteworthy is that William the Conqueror had many supporters, even though the nobles and clergy did not support him.
Although religion had such a greater influence at that time, many people found it unfair that a nephew to inherit the wealth and not his own son.
Catherine the second, the tsar of Russia, made a lot of children, each one with a different man, but in documents they all appeared to be the children of the former tsar, her husband, jailed by her.
Another case is that of Petru Rares, son of Stephen the Great and Rareşoaia. He ruled Moldavia two times. Stephen the Great had forty children, most of them with different women, not with his wife. Through a will, Stephen the Great has recognized all children. He took this decision after one of his sons fell in love with one of his half sister, without actually knowing that she is his half sister.
Another famous case is of the ruler Alexandru Lapusneanu who ruled twice, as Petru Rares did.
Anyway, the first progressive state that took care of this problem is Italy. Many parliament members and nobles had children with women whom they were not married so they passed the law of recognizing illegitimate children. Any man married or not, legally could recognize his child with a woman who is not his wife, so that the child would become legitimate.
The communism has made the most progress in this regard. If the man did not admit that he is the father of the child, he could be sued. Moreover, the man could sue his own wife if he considered that the child is not his.