An embarrasing revalation.

Before chi-chi could give bulma and number 18 an answer they were interrupted by an unexpected sound.
"HAHAHAHAHA! Oh I can't believe this, this is just to good! A HA HA HA!"
Vegeta had come closer and was laughing so hard there were tears in his eyes.
Bulma gave him an angry look. "Vegeta please were trying to have an important conversation here!"
"Don't you see woman? Goten is a super saiyan and if kakkarot's woman hasn't slept with him since three years before goten's birth that can meanb only one thing."
Bulma thought for a moment then gave vegeta a stare that could have melted steal. "VEGETA! You didn't!"
Vegeta stopped laughing long enough to get a disgusted look on his face. He sneered at bulma as he replied. "Please! As if I would ever want kakkarot's left overs."
"But if it wasn't you or goku then who?"
"There aren't any other saiyan's alive, it had to be one of you."
"Actually that's not true bulma." Number 18 interjected. "There is one more saiyan."
"Who?"
"Think about it woman. If goten's father is a saiyan but is not kakkarot or myself then it would have to be gohan."
"WHAT?!" Bulma fell over backwards at the revalation. Quickly composing herself she asked chi-chi. "Chi-chi, is that true?"
Chi-chi hung her head in shame and a deep blush came to her cheeks as she answered them. "Yes its true. Gohan is goten's real father."
"But but how? How did this happen and why?"
"I'll tell you but you have to promise to not tell anyone else, especially goku."
"How can he not know?" Number 18 asked. "He hadn't slept with you for three years before goten's birth. He has to know he is not goten's father."
"Actually, Goku is a bit naive in a lot of ways. I've known him longer than anyone here so believe me when I say he really hasn't figured it out." Bulma explained goku's innocent nature to number 18. "Don't worry chi-chi we promise not to tell anyone. That meens you to vegeta!"
"Oh believe me I would not pass up the opportunity to see kakkarot embarras himself further."
"Well o.k. then I'll tell you. It happened right after the cell games,......"