Can boys be made gay if given dolls to play with instead of more masculine toys?

Also even if allowed to play with trucks and toys guns etc would acting gay as a child determine theri sexuality. Also the opposite question for girls. Would girls who engage in masculine activities turn out lesbian? My little brother is gay and effeminate acting. I remember as a young child he enjoyed whenever me or my friends would play ":dress up" with him. He never played with dolls but wearing female clothing and making himself look "pretty" lasted as a preferred activity. When he became 13 he started noticing other boys in a way that was not normal such as commenting to me that some boys were sooo cute and he "loved" to watch them play sports etc. At 14 he had his first bf and went from movie dates and hand holding to making out and kissing etc. My parents did not know he was gay until after he told them that he was in love with a certain boy and that they had expressed their love for each other. He has never had an experience with a girl.