I'm married and have a baby. And since he is my first kid I wish to wear gold for him but my family is opposing to wear. Can we wear gold for boy baby in Islam?
Gold is forbidden -to wear- for males, but allowed for females.
See for example this hadith from sahih Muslim about rings and the prohibition of drinking from silver or gold vesells.
Or this one on your Issue from Jami' at-Tirmidhi.
But your son could wear silver instead of gold.
And Allah knows best!