We are born of equal disposition. At birth, infants have survival instincts such has the desire to suckle and a taste for mother's milk. They don't have to be taught to drink from a mothers breast, it just happens. They learn to move around so they can get to more food and keep the brain and body growing. That's our primary objective until we reach about age ten which is when we start to have a sexual identity. Some male children do show more feminine behavior than others. But, that has more to do with environmental influences. Often, they identify more with the mother and less with the father. Fat kids tend to have more feminine behavior because they don't play games which we identify as "manly" and tend to have fewer friends and spend more time at home with their mother. But, that doesn't mean they are gay. Our sexual identity is much deeper than that.
Genetically, our sexual identity is genetically predispositioned in that certain areas of our brains develop before others. That is what makes the difference, the infinite complexity of our brains and the chemistry within determines how we see ourselves and whom we are attracted to. Despite what anybody might say, there is no accurate way to determine what an infant's sexual orientation will be and there is no way to "change" it. Some gay men force themselves to live a heterosexual lifestyle because they are psychologically programmed to accept it. But, it tends to be an empty, loveless relationship and often leads to depression and identity conflicts later in life.
So, parents can chose to let their child find himself or they can force their prejudices on him and make him hate himself for feeling the way he does which often guarantees an empty, unfulfilled life. If it weren't for prejudicial parenting, there would be a terrible shortage of sociopaths in the world. Crimes related to sexual dysfunction would dwindle and we wouldn't have some of our most heinous crimes. There would be fewer people turning to alcohol and drugs. It could completely change the economy and would make CDG less interesting.
Hate has its benefits.