Did Michael Jackson have biological children?

I've always wondered about that, why do none of his children even have a hint of black genes in them

It's possible, the public just doesn't know.

His children are biological but they are not his.  It would have required him to either have sex with a woman, god forbid, or provide a sperm specimen to a suitable surrogate.

what is biological children?

None of his children look black, but they would if he was the biological father. 

Micheal  Jackson was the biological father to 3 childen,

Yes he does. Blanket is just one of them.

By looking at them, I'd say no. There is always mystery and innuendo about him, never straight truth and facts. 

I believe so. I think he was the sperm contributor to all his 3 kids. 

I doubt it. Although he had a condition (vitiligo) and then he blanched an plastic-surgeried himself into something vaguely similar to a white person, he was black and his children would have had to necessarily look at least a bit african-american.