So what happened to the sperm from the man with the half Asian kids? Is some Pakistani family raising his child?
Since the story is not mentioning any children who are biologically his, whatever woman got his genetic material did not have a baby as a result.
Sh!t happens. Remember the story many years back, about Kimberly Mays, who was discovered at age 10 to have been switched at birth, and given to the wrong parents? The switch was discovered when the other child died of heart problems that had been evident at birth, and Kimberly's life was a general wreck after all the legal battles and emotional turmoil.
http://www.cnn.com/US/9906/25/mays.hearing/
The Kimberly Mays case was apparently not accidental, but rather arranged by a doctor who decided one set of parents was more deserving than the other, and should therefore get the healthy baby.
http://www.amazon.com/gp/product/067940015X/002-6776573-2736063?v=glance&n=283155
Actually there are quite a lot of "switched at birth" cases, some accidental and some deliberate, but most are discovered much sooner (or not at all). Imagine getting hit with this info right as you're (or your child is) hitting puberty.