Which of the following does not predispose to leukemia
Leukemia risk factors
1) General

Gender: Men are more likely to develop CML, CLL and AML than women.
Age: The risk of most leukemias, with the exception of ALL, typically increases with age.

2) Genetics

Family history: First-degree relatives of CLL patients, or having an identical twin who has or had AML or ALL, increases the risk for developing the disease.
Genetic diseases: AML has been associated with Down syndrome, Klinefelter syndrome, Patau syndrome, Fanconi anemia, Bloom syndrome, Ataxia telangiectasia, and Kostmann syndrome, may play a role in the development of leukemia.

3) Smoking

Smoking cigarettes does increase the risk of developing AML

4) Exposures 

Radiation : Exposure to high-energy radiation (e.g., atomic bomb explosions) and intense exposure to low- energy radiation from electromagnetic fields (e.g., power lines). 
Chemical exposure: Long-term exposure to chemicals like benzene & ethylene oxide is considered to be a risk for leukemia.
Drugs - alkylating agents & topoisomerase II inhibitors increase the risk of AML.

5) Previous Cancer Treatment

Certain types of chemotherapy and radiation therapy for other cancers are considered leukemia risk factors.
Alcohol
Genetic disorder
Smoking
Chemical exposure