help. what would you do? any mums had this happen?

ok so i never knew my father at all. im not fussed on meeting him either.
my mother actually is freinds on FB with him. yesterday i said to her can you please get in contact with him and ask if i can msg him as id like to ask about medical conditions in his genetics.
ive been warned that i may have a few other medical conditions within the next few years. i asked my nan and my pop what genetics run in the family and only one of them that i could very possibly get runs on our side so i started thinking maybe its runs on my fathers side. so i asked if my mum could contact him and ask whether i could contact him and she said no, so iasked if she could contact him for me and she again said no . i said why not, i only want the medical history and ill be lucky to get the information out of him? and she just said. (angry tone) just stop worrying about it!!!
i said these conditions can be serious and i want to know if its something in my genes or whther theres something else going on in my body..
and she said ( angry tone and glaring at me) stoping whinging and just get over it.
shes always said to me that if i wanted to get in contact with him she would allow me to, if i wanted to talk about him she would and ive asked a few things about him before and she answered them for me. i understand that its probably hard for her to talk about her ex but i said that i would do it. i would do just as everyone was telling me to do -grow up- so i said i would contact him can i just have his fb details (doesnt go under the name i know) and ill ask him myself.
im not really sure sure what to do.... i dont have the best relationship with my mum so i need a 'spare' or a few spare forums mums lol. im lost and really dont know what to do about it? or do i just leave it and not worry about it?