In my case, I'm still brazilian and portuguese... If I have children, they will be the nacionality where they born and for what I understand I'll be able to get portuguese nationality to them (if it is still avaiable at the time, I believe not, looking at the wave in Europe against immigration)
Each country has it's law for nationality given to sons... I know some has restrictions about how many generations can get it, today portugal has no restriction... I have no clue about English law about, If I were you, I would get a look at the laws about it, perhaps your kids can take the English nationality, perhaps not... Some has restriction about male or female, as Italy... If the wife is Italian, her children won't be able to nationality (if not her children, her grandsons), if the husband is Italian, them they can get it...