How I Met Your Father Has A Good Reason For Keeping The Son Hidden
"How I Met Your Father" has a lot in common with the original "How I Met Your Mother." Both shows focus on the dating lives of a bunch of young people in New York City, and they're both centered on the main character telling their future children about how they met their future spouses. The big difference is that the future scenes of the spinoff feature Sophie (Kim Cattrall) speaking to her off-camera son, whereas the original show gives us an off-camera future Ted (Bob Saget) talking to his on-camera kids.
As Hillary Duff pointed out, showing what Sophie's son looks like would give away too much information about the identity of the father. In the original show, the sight of Ted's kids made it clear immediately that the titular Mother would be white, which meant that every non-white woman that popped up on the show (admittedly, not many) was immediately written off by audiences as a potential candidate. The spinoff, meanwhile, leaves itself a wider net of options. Until they show us what the kid looks like, the possibilities for the father are endless.
Not only about race
Even beyond confirming the mother was white, the flash-forwards in "How I Met Your Mother" also heavily implied the mother would be a brunette. This would be made even clearer in season 4's "Shelter Island," where the show treats us to future Ted's vision of what his current life would look like if he'd married Stella (Sarah Chalke) as planned. In the vision, he still has a son and a daughter, but they're both blonde like Stella. In stark contrast to how genetics work on "Game of Thrones," brown hair is the recessive gene as far as Ted's fantasies are concerned.
The original show also narrowed things down even further in its season 1 Thanksgiving episode, in which young Ted (Josh Radnor) meets a stripper named Tracy. "And that, kids, is how I met your mother," the older Ted says. The kids freak out before Ted assures them he's kidding. "Your dead mother used to be a stripper" is kind of a weird prank for Ted to play on his kids, but most notably, it's a prank that only works on them because he uses the mother's real name. The fact that they fell for the joke makes it clear: whoever the mother turns out to be, we know her name will be Tracy. For such a quick, one-off joke, the moment removes a surprising amount of mystery from the show.
Although it's debatable whether "How I Met Your Father" has fully emerged from the shadow of the original show, at least it improved on its predecessor in one major way: the father in this show truly can turn out to be anyone.