Family matters

Solange's mentioned again: ''Mum somebody, somewhere, somehow in your family or dad's family, in my background, must suffer like me from allergies. We are already two: Kilian and myself.''
She has a point, I need to find out more, about eventually existing allergy history.
How do you take off for such a research?
I can try to get in contact with people who are involved in these fields of research.
Does it really matter? Does it help if we know?
It could give some clearness and understanding.
And maybe these two kids just happen to be the only ones with their food related symptoms.