It's a good idea to record the birth of an American child born abroad at the consulate, there is no law requiring that this be done. Failure to get this certificate and registration does not affect the citizenship of the child.
In most countries, this would be done as a matter of course, because it is a prerequisite for a passport, local visa, etc. But Canada did not at that time require a passport or a visa for US citizens, nor did the US require a passport for returning US citizens or for Canadians either. So there would have been little compelling reason to register the birth at the US consulate.
Frankly, failure to register the birth at the US consulate is a bit irresponsible, but it isn't fair to blame the parent's irresponsibility on the infant.
How else would Cruz evidence his citizenship? If you don’t have a U.S. birth certificate, it stands to reason that you have to have another document of some sort evidence your citizenship.
So the question becomes,
for —anyone— born in canada in that time frame, under the same circumstances
(parents married, one a US citizen, one not, mom 19 or older when gave birth)
what were the effects of not having a US birth cert?
And for not having the Record of birth abroad recorded at the US consulate?
If the parent didn’t have it recorded the year the child was born, could they file it later, when they found out they needed it?
In my previous reply, the “19 or older” is for the case of mom being the US citizen.
I think if its the dad who is the US citizen, there may just be the requirement to file the birth abroad with the consulate.