Gohan nearly spat out his food.
"What?!" he demanded around a mouthful of noodles.
Bulma sighed and sipped at her tea before answering. "You've heard of mules, right? Ligers?"
Scratching the back of his head, Gohan nodded uncomfortably. Of course he'd heard of them. His eyes flickered across the Briefs' huge and well kept lawn, to where Goten and Trunks were playing a Super Saiyan version of tag. All three of them were the product of a Saiyan male and a Human female.
"Well, do you know why they're infertile?" A shake of the head. "It's because the parents are just too different. The chromosomes don't line up correctly." Bulma watched the two boys as well, concern written all over her face.
Videl wanted kids. Gohan knew she did, by the way she acted around younger children. Her tough demeanor was replaced with a protective gentleness that he saw in his own mother, even when she was scolding him. He wanted to marry Videl; he'd bought the ring and was just waiting for the right moment to pop the question.
"Of course, it's also very possible that you're not sterile," Bulma continued quickly. "I ran some tests on your father and Vegeta and, whether the Prince likes it or not, Saiyans are very similar to humans… Aside from the whole hair thing, and the sheer density of their muscles and bones… and the extra layer of muscle around the abdomen that protects vital organs… and their teeth which, like a shark, they never run out of… and the tails…"
Gohan groaned and rested his head in his hands. "How do we find out?" he asked, dreading the answer.
Bulma brightened and pulled a small plastic cup with a lid from her purse. "I need a sample."
A smiling receptionist had directed him to Bulma's personal lab, and he'd found her sitting at a computer. She grinned and invited him to take a seat next to her. "Is this good news?" he asked.
Bulma winked at him. "You bet it is! Ever heard of heterosis? It's the tendency for outbred strains to exceed both inbred strains in fitness."
Squinting in thought, the demi-Saiyan worked out what she'd just said. "You mean… like how mutts have less health complications than pure breeds?" he mused aloud, his voice growing with excitement. "Are you saying that Saiyans and humans aren't too different after all?"
"Exactly!" Bulma chuckled and pulled up a magnified picture of what Gohan assumed was his… sample. "You're not a liger after all, you're a healthy labradoodle. From the looks of this sample, you're more virile than Goku or Vegeta." She frowned suddenly. "Of course, I am just comparing one demi-Saiyan to a mere two Saiyans. Were it not for their planet-destroying tendencies, I'd wish there were more Saiyans around to study."
"So I'm not…?" Gohan let the question drop and laughed shakily, leaning back in his chair.
Bulma looked longingly back at her lab table. "Do you mind if we take a few more tests? If my theory is right, we should find that your body exceeds Saiyan and human standards in other ways. I'm thinking that your bone structure might-"
She continued on like this while she took blood and tissue samples. All Gohan felt was the weight of a diamond ring in his pocket. After such good news, Bulma could take all the tests she wanted.
A/N: Before anyone complains, I am NOT saying that infertility would wreck anyone's relationship/marriage, or that children are required to maintain a happy marriage. However, it is a trial that many couples cope with, and for Gohan - who's half human and half frickin' alien - it's a more legitimate concern than most.