Quote Milkshake24: It's a guarantee that she changed the results, however that doesn't mean someone like Victor hadn't had them tampered with before hand. Summer could still turn out to be Jack's. Sharon swapping the results would than be a slap on the wrist while Victor takes on some heat. Just saying that the door is still open for more to this story than meets the eye without Sharon imagining that she did it.Look at Kyle and Abby results from Jack and Nikki tampering with Victor's frozen sperm. If Ashley,Jack and Nikki could all get theirs hands on frozen sperm it's just as Easy for Sharon to get into a lab and swap results as well as someone working for Victor.
or sharon could have done it all on her own like we have heard from her own mouth :)