Alexander Zverev was rumoured to have diabetes for a long time before he finally publicly admitted and launched a foundation to support people with the condition.
Zverev was spotted with diabetes assistance devices over the years but never publicly admitted to suffering from the condition. He was diagnosed at age 3 leaving his parents frightened about his future and what life might look like.
"My parents were very scared. They were very worried. Mum was crying a lot. A lot of parents get intimidated by a lot of doctors who say 'your kid is very limited', which is not the case. I always said to the doctors, 'yeah, well, I want to play tennis. That's the only thing I really care about'
Opting to continue playing tennis was a decision he had to make because some suggested that it would be better to stop. It was not something Zverev wanted to hear and it made him really upset.
Some of them said, "No, you have to stop ... there is no way you can be a professional athlete with this kind of illness. There is no way you can play such a hard physical sport. "This is what really stuck in my mind, made me quite upset, to be honest. I don't think you should set any limits to kids, because I think that is just not fair to them.
He also revealed that he hid the disease because he was embarrassed about it. Today he is proud and wants to be a role model for people with it.