Yes. There is a reason always. But you may change it in many cases.
There are five Niyamas(laws) which control everything. Which one is powerful it will win. So, if your mid(Citta Niyama/Order of mind) was powerful you could change it. You can get necessary mind power by doing correct mediation(stop wander of mind and concentrate mind on one thing). But main thing is Karma. From our born to death, everything mainly happened according to karmas which we have done in previous lives ( But there are other four Niyamas). Getting a good appearance, good house, good friends, good job or good wife everything mainly happened according to Karma(But we can change it if we have good Karmas with us). Karmas we are doing in this life mainly get on to action in the next life, that’s why many people don’t believe it. According to Buddha if you don’t believe karma it will be a very bad karma called "Mithya Dushtiya" which will definitely make very bad results.
You(your generation of minds) will rebirth according to what you have done(Karma) in this life(or in previous lives) since you have not attain enlightenment(eternal happiness). If you have done many good deeds you will rebirth in a good place(heaven, human realm). But if you have done many bad deeds you will rebirth in a bad place(Animal realm, evil spit, daemon, hell animal). There is no supernatural being that determines anyone's fate of its own will and everyone is responsible for their own actions and their consequences. I think it is same as Newton's third law of nature. If you have done any of five bad crimes or sins(Anantarika-karma) you will definitely reborn in a hell world. No one even a god can't stop it.
When your last mind(Chuthi Chiththa) vanish from your body(death), your next mind(Prathisandi Chiththa) will start in a new body(birth) but no time delay for this(according to Abhidharma) even if you rebirth in a far away solar system(Isn't this wonderfully? Mind is the most fastest thing. fastest than light).
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* You do good deed, good result return. You do bad deed, bad result returns.(There is Karma)
* Helping or gifting to a virtuous person will return many good deeds than to a normal person.
* There is a life after death.
* There are extraterrestrial worlds (including hells and heavens). Some animals came here after death; some animals go there after death.
* Helping or gifting to mother and father will return many good deeds than to a normal person.
* There are some animals who born instantly from their karma without mother or father(Such as gods)
* Rarely, unusual intelligent men are born. Some of them are becomes monk and concentrate their mind with meditation. Some of them are getting unusual intelligent and will discourse a great teachings saying how to become happy forever (Four Nobel Truths). They are called Buddha’s.
[Noble Eightfold Path - Right View]