How in the world do I potty train my boys??

Potty Training Concepts has the answer:

While there is definitely no right or wrong way to potty train a boy, most potty training experts will recommend that toddler boys should be potty trained sitting down. Even the American Academy of Pediatrics recommends encouraging & teaching toddler boys to urinate sitting down.

The major reason for this recommendation is to keep things simple by teaching them to sit for both urination and bowel movements. Other reasons include the logistics involved in managing the equipment for both types of training and the effort required to clean up while they learn to aim properly.

My personal recommendation is to first teach your son to potty training sitting down. Once he completely potty trained for both and is accident free, then I would recommend training him to pee standing up like his father and brothers!!

Keep it Simple and Bowel Movement Training:

Most parents would agree that potty training your toddler son includes not only teaching him to urinate in a potty or toilet, but also to make bowel movements in the potty or toilet. And for bowel movement training, you will have to teach your toddler son to sit down on a potty or the toilet.

So, then if you decide to teach your son to pee standing up, you will have to teach him to have a bowel movement sitting down - that means teaching your son two different things. This can get confusing for a toddler.

Let's take a look at the potty training process in detail from the child's perspective. 

It starts with body awareness and the ability to associate a feeling of fullness with the need to eliminate and the result i.e. a BM or urination. This awareness starts at about age 1 and until now (for the last 1-2 years), when you child has this feeling, he simply goes ahead and eliminates in his diaper or pull ups. Now you want him to learn that when he has this feeling he has to stop and find his way to the potty. Then he has to remove his clothing and then sit or stand on the potty depending on which feeling he has and then eliminate.

So, from your child's perspective you are already asking him to do a lot - and by trying to teach your child to stand while urinating and sit while having a bowel movement, you are asking him to only learn and identify the feeling of fullness, but to differentiate the two feeling and make a decision to sit or stand.

Having said that, bowel movements usually occur with urination, and if you child is sitting down to urinate, he may have a bowel movement at the same time and thus make the whole potty training process a lot easier.