User blog comment:SSWerty/The Swetty reviews/@comment-3122168-20110325070633/@comment-3122168-20110325071708

Okay, then. Well, he knew that Kordar's wife was pregnant because, when he went over to Kordar's house to speak to Yamcha and Kordar, he sensed a little baby inside of her. He therefore knew she was pregnant. When it came to the final fight, he simply made the intuitive assumption that she was giving birth.

As for why he knew Kordar was his dad, well, it's somewhat hard to explain. It was simply in his actions; his honor, his bravery, his strength, etc. that Tien finally came to the epiphany that he was his father. It was more or less something he felt internally, an automatic conclusion he came to. I know, it seems a wee bit convoluted.

Oh, and your Q&A page needs an update. Just sayin'.