First of all, from the perspective of customs and habits, ancient people thought that their daughters would become other people's families after marriage, so it was considered unlucky to hold a birthday party at their parents' house. This is because in ancient times, people generally thought that birthday was the most important day in a person's life. If something bad happens on this day, that person's life will be affected. Therefore, in order to avoid possible bad luck, people usually don't celebrate their married daughters' birthdays at their parents' homes.
Secondly, from the perspective of feudal ethics, the ancient ethics of China stipulated that women should give priority to their in-laws after marriage, and should not attach too much importance to the family. Therefore, it is considered as a disrespect for the in-laws and a challenge to feudal ethics for the married daughter to celebrate her birthday at her parents' home.
In addition, there is a saying that a married daughter will "rob her parents' birthday" if she spends her birthday at her parents' home. Because in ancient times, people thought that everyone's birthday was born. If a married daughter celebrates her parents' birthday, she may "rob" her parents' birthday, which is unlucky for them.
Generally speaking, a married daughter can't spend her birthday at her parents' home, which is mainly influenced by ancient customs and feudal ethics. However, with the progress of society and the change of ideas, this traditional concept has been gradually broken, and now many families no longer adhere to this custom.