Why not? Give it.
Along with the GI joe, racing cars, machine guns and bat-ball ...give him a doll too. Don't tell him it's girly, don't tell him it's not something boys should not play with.
Just give it to the kiddo like any other toy.
He may pick it up and toss it aside himself (and you would breathe a sigh of relief. First test of 'man'liness passed.)
In that case, the matter will be over. OR he might start taking an interest in it. Pick it up and try pulling apart it's limbs, tearing it's hair and banging it on the floor.
He might be very interested in what lies beneath the skirt (you MAY try to stop him. Although you will breathe another sigh of relief. Manliness reconfirmed)
It's nothing dirty. Let him examine it if he wants to. It's basic innocent childish curiosity.
Le's turn to more dreadful prospects. Shall we?
He might start playing with it. Maybe brush it's hair or sleep next to it. He might give it a cute name and dress it up occasionally. He might make a house for it and put little makeup on it.
You will fight your impulse to snatch the doll back. good. fight.
He might like setting it's hair and end up being the best hair designer in the country. He might like dressing it up, and become an artist or a designer in life.
Hell! Let's assume the 'worst'. He might like dolls because he is gay. Well then, you can always blame the doll in the future. Blame the doll and reduce his inner burden of guilt.
It will teach him to be delicate, to handle things with care.
If he whispers secrets in her ears, it might make him more open to women. It might teach him to trust. It might teach him respect for women.
He will build the same house for a girl later on. He will hold another girl close to him, in the future. Only this time, he will know how to hug her without hurting her.
It will make him more emotional and more deep within. It will teach him not to eye a woman with lust alone. It will make those hands more tender.
The XY chromosomes will come into action. He will become the man he is meant to be. Nothing can prevent that from happening. It has been coded into his genes. Hormones will take care of it.
All you can do is, help him become a good human being.
So, give the boy a doll. He will definitely be a better man. And a real doll will love him back, for it