The Cushion Saturation - S2-E16
Continuity mistake: When Howard and Leslie are in the paintball shed, Howard's paintball ammo pack is closed, but when he and Leslie start kissing, it's open.
The Hofstadter Isotope - S2-E20
Continuity mistake: Near the end of a conversation with Stewart, Penny is holding a drawing that Stewart drew for her. In the next shot, it is now on the counter and she is picking it up.
The Classified Materials Turbulence - S2-E22
Continuity mistake: Leonard is talking to Stuart at the door to his (Leonard's) apartment. Howard then comes over and slams the door in Stuart's face and Leonard has moved back about 4-ft instantly.
The Lizard-Spock Expansion - S2-E8
Continuity mistake: The way Leonard holds the can of Diet coke before he puts it down changes between shots. (00:00:25)
The Bath Item Gift Hypothesis - S2-E11
Continuity mistake: When Penny takes a drink from the egg-nog carton before kissing Leonard on the cheek, between shots the logo-branded label changes which direction it faces in her hand. (00:16:45)
The Vartabedian Conundrum - S2-E10
Continuity mistake: When Stephanie asks Leonard why he hasn't told her about Penny, he spills some of the pancake mixture out of the bowl he is stirring. In some shots the spilled mixture vanishes and the appears again.
The Maternal Capacitance - S2-E15
Continuity mistake: After Leonard's mother says, 'Tell me about it', her head was tilted downwards, but in the next shot, she was looking straight again. (00:04:35)
The Vartabedian Conundrum - S2-E10
Continuity mistake: When Leonard, Raj and Howard are talking about Leonard's new trousers, the items on the tray behind Howard keep changing.
The Classified Materials Turbulence - S2-E22
Continuity mistake: When Raj is going through the ideas on what would work to fix the toilet, Sheldon's hand is not near his face, but when Howard talks about moving to Israel, Sheldon's hand is up by his face.
The Monopolar Expedition - S2-E23
Continuity mistake: When Penny finds out about the expedition, Sheldon starts to walk to his apartment. Camera cuts to Leonard in the apartment for five seconds and then to Penny in the doorway. Behind her, you can see Sheldon walking to the apartment still. Since he was halfway to start with, he should be in the apartment by now. (00:10:35)
Suggested correction: Genes can be dormant. Which allows them to skip generations. Therefor Missy's children could actually get the "mutated" gene. This is especially true since Sheldon and Missy are twins. Also, since the episode is about who out of Leonard, Howard or Raj, Sheldon would allow to "mate" with his sister, there is the added "insurance" of getting any smart genes from any of the 3 Lothario's mentioned above.
If you are going to try to argue with a geneticist about genetics, please use the correct terms. Sheldon is not referring to a recessive gene - there is no such thing as a dormant gene - he is speaking of a randomly mutated gene. Those are the words he used. If he had inherited a homozygous recessive karotype - one recessive gene from each of his parents - then somewhere in his family tree there would similarly gifted people, in which case he would use the correct term - a recessive gene. If Missy is a heterozygotic dominant karotype possessing the recessive gene for super-genius and the dominant for ordinary intelligence then mating her with Howard, Raj or Leonard would be a waste of time as their dominant genius gene would prevent the recessive super-genius gene from being expressed in the phenotype of the resulting child. The child would be highly intelligent but not on Sheldon's standards. It doesn't matter if Sheldon does not know any of this as he refers several times to a randomly mutated gene, not a recessive one. Missy does not carry the super-genius gene. The posting is correct.
Sheldon is prone to magical thinking when necessary to preserve his obsessive need to control his environment. He may have simply ignored the flaw in his reasoning, as even the most intelligent humans do when venturing outside their ares of expertise. He may be interested in the science of genetics, but his Ph.D. in physics doesn't qualify him as an expert in that field.