No! The existence of a behavior doesn’t mean it has to be natural or by birth!
The existence of homosexuality in human behavior doesn’t mean they are born that way! Similarly, the existence of homosexuality in animal behavior doesn’t mean they are born that way.
Again, “Just because something is doesn’t mean it is ought to be”
Obviously,the existence of homosexuality in animal behavior, can never mean humans are born that way! This is another logical fallacy, a false analogy.
In short, existence of gay behavior in animals doesn’t mean humans are ought to be so!