A/N: A slightly different take on the idea of the Doctor and Rose having a child. A little sad near the end. I got the idea in science class and it wouldn't stop bugging me... May do more than just this oneshot, depending on how well this goes down.

It was inevitable. Rose Tyler had always known her son would be different. She just never expected it to be that obvious. She forced herself to smile as Jackie's friends made well-meaning- if a little hurtful- comments about Jack as he played with his father on the sitting room floor. The Doctor, of course, seemed oblivious to the comments Bev and Maureen were coming out with, but even Jackie looked a little uncomfortable with the conversation. Settling her head against the back of the sofa, Rose closed her eyes, feeling exhausted. It was no one's fault, of course; the Doctor was an amazing dad, and was very hands-on. But the truth of the matter was Rose was a twenty-one year old mother, barely prepared for motherhood, not to mention barely prepared to care for a disabled toddler. Jack Peter Tyler was everything the Doctor and Rose could ever have hoped for, and more; he had his mother's eyes and his father's wild hair, but he had been born with Down syndrome. The Time Lord genes he had inherited from his father had minimised it a bit, and made his facial features look pretty much normal, but it was still mosaic Down syndrome, and he'd never be as intelligent as his parents had expected a human/Time Lord child to be, but they loved him regardless.

"I 'eard that Down syndrome kids can't walk or talk for ages." Bev stated, watching little Jack carefully.

"Nah," the Doctor replied dismissively, grinning at his son "Jack's already started walking though he's a bit shaky still. Also, he can only really say stuff like 'mummy', 'daddy' and 'gran', and he hasn't quite got the hang of hand-eye co-ordination yet but he's doing very well."

Jack, however, was oblivious to the conversation going on around him as he focused solely on stacking the large wooden building blocks, the Doctor helping him.

"So soon? I mean, I know he's only partially Down syndrome, or whatever they call it, but surely he shouldn't be doing that so early on?" Maureen asked in confusion.

"Mosaic." Rose whispered in annoyance, opening her eyes.

"Pardon?" Maureen asked, frowning at the young woman.
"It's not called partial Down syndrome. It's mosaic Down syndrome." Rose replied, watching Jack with a small, blissful smile on her face.

"Anyway, Jack's a little star, that's what he is." Jackie piped up.

"You're getting help with him?" Bev asked Rose.

Rose just grinned at the Doctor, who grinned back.

"Oh, we don't need help. We're getting along just fine. The Doctor knows of these teaching method thingies that help Jack learn things better and easier." Rose explained.

Both Maureen and Bev nodded in understanding.

"I must say I admire your courage; I really don't understand how you can cope with him." Maureen told Rose wistfully.

"To be honest with you, I couldn't imagine our lives without him." Rose replied quietly.

"He's one little kid to have you two as his parents. You're both so brave." Bev told Rose and the Doctor.

Rose smiled weakly.

"To be honest with you, it takes everything I've got some days to simply not fall apart." Rose answered quietly.