Yes, you read right. Bring the smartphone in jeans affect the sperm of the person carrying the smartphone in any of the front pockets of his trousers. Previously it was said to use the smartphone near the heart was not recommended.
Carry your smartphone in jeans would affect sperm mobility and also in the amount in which they reproduce. Some scientists in Britain are doing more studies to be sure 100% of these risks.
In all it is advisable do not recommend carrying the smartphone in the pants pocket, so you can make sure your sperm are in good condition to conceive with your partner later. Better safe than sorry.