(This question has been heavily edited from its original version, please view the revision history if an answer or comment doesn't make sense.)
I can only think of two ways this could happen in Shadowrun, and I'm not certain either of them apply in canon. In earlier editions of Shadowrun, when goblinization was still reasonably common, a child could change metatypes during their childhood or adolescence or be born a different race than its parents. The problem is that the Fifth Edition books give no real indication that this still occurs spontaneously - but it doesn't specifically say it doesn't, either, so I'm looking for other guidance, maybe from less recent books or non-rulebook novels and such.
The other way is if mixed parents could produce children from either parents' metatype. If that was ever in canon, it should still be valid, but I'm not familiar with every edition of Shadowrun (and 5e is the first one I've gotten anything but the corebook for), so memory will not serve to answer that question for me.
Can it be done without significantly bending canon, and if so, how?