If both beta globin genes code for the sickle protein, the person has sickle cell disease. Sickle cell disease is determined at conception, when a person acquires his/her genes from the parents. Sickle cell disease cannot be caught, acquired, or otherwise transmitted.
For every year of the cat's life after age 2, one cat year equals approximately 4 human years. This is based on how cats mature - for example at around 10 - 11 human years most cats start to slow down quite a lot... This is when they're getting to about 60 years old in Kitty terms.
Probably about 20. Although 20 years old for a cat is about the same as 100 years old in a human, you can't simply divide the numbers. If this was the case, 1 year old for a cat would be about the same as 5 years old for a human. This is a problem however, considering just how long it takes for humans to mature compared to the rest of the animal kingdom. A cat is usually fully grown at around 1 year old, perhaps a bit later.