Traumatic Experiences: Many phobias start after a person has a frightening or traumatic encounter with a specific object or situation (like being bitten by a dog, which could lead to cynophobia — fear of dogs).
Observational Learning: Even without a direct experience, just seeing or hearing about someone else’s negative experience can cause a phobia. For example, a child watching a parent panic during a thunderstorm may develop astraphobia (fear of thunder and lightning).
Genetic Predisposition: Some people may be more prone to anxiety disorders and phobias due to their genetic makeup. If a close family member has a phobia, it can increase the likelihood that you might develop one too.
Learned Behavior: Phobias can also stem from how we were raised. Overprotective or anxious parenting, for instance, can lead a child to see the world as a dangerous place.
You’re very welcome!

Thank you Erica for sharing your very detailed comment