“All right. I assume you collected sperm samples from men in both groups.”

“That’s correct.”

“What kind of analysis did you do?”

“The first step was a standard semen analysis. I wanted to make sure that I was dealing with sperm samples that fell within normal ranges. Particularly with respect to motility and forward motion.”

“Would you explain those terms, please?”

“Motility refers to the extent to which sperm actually moves. Like the old macho saying, ‘My guys can swim.’ If they don’t move, they’re fairly useless. Swimming, however, is not the be-all and end-all. If your sperm is doing the backstroke, you’re probably not going to fertilize the egg, either.”

A little laughter wafted across the courtroom. Even the judge smiled. The prosecutor said, “So, forward motion is a separate component of motility?”

“That’s right.”

“That makes sense. What was the next step of your analysis?”

He grinned, as if too pleased with himself. “Not to pat myself on the back too firmly, but this is where my analysis was somewhat groundbreaking. I examined the motility of sperm in two different environments. First, I looked at each man’s sperm in isolation and took my measurements. Once I’d done that, I would introduce the sperm of another man into each man’s sample. And I got the most interesting results.”

“What did you find, Doctor?”

“In both groups of men, some of the motile sperm continued to swim forward, as if headed straight for the egg. Other motile sperm, however, swam directly toward the foreign sperm. These sperm attacked the invader, pummeled it, and destroyed it.”

“What did this tell you, Doctor?”

“My conclusion is that men have two kinds of sperm. One has fertilization as a primary mission. The others act like soldiers, making sure that the invading sperm never reaches the egg. I call them assassin sperm.”

“And you say this was true in both groups of men?”

“Yes, both groups had assassin sperm. But here is where the results became very interesting. The men who were paired in a monogamous relationship had relatively few assassin sperm. By comparison, men who were involved with women who had multiple sexual partners had far more assassin sperm.”

“What accounted for this difference?”

“In my opinion, it is purely a psychological component-the man’s state of mind. If he believed he was the only candidate in search of the egg, his assassin sperm count was low. But if he believed that he was in competition with another male, his body produced additional assassin sperm.”

The prosecutor paused to allow the jury to absorb that crucial point. It wasn’t clear that they understood where this was headed, but Jack knew-and he was planning his objection.

Torres said, “Let’s get back to your examination of Captain Oscar Pintado. Did you do an analysis of his sperm?”

“Yes I did.”

“What kind of analysis?”

“The same analysis I just described. I did a standard analysis first, which revealed that his semen fell within the normal ranges, including normal motility.”

“Did you then test his sperm with…how should I put this? Invading sperm?”

“I did.”

“What did you find?”

Jack was on his feet. “Objection. Sidebar, please, Your Honor.”

The judge straightened in his chair, then waved them forward. They gathered out of earshot from the jury and witness.

Jack said, “Judge, first of all, I’ve never heard of this assassin sperm analysis. The very idea of a man’s sperm doing kung fu on some other guy’s business and then slapping microscopic high-fives all around sounds a little ridiculous.”

“It’s accepted science,” said Torres.

“Maybe it is,” said Jack. “But in this case, the doctor’s testimony amounts to nothing more than a sneaky, backdoor effort to prove that my client was unfaithful to her husband.”

“It’s not the back door. We’re talking about a scientific analysis of her husband’s sperm. Captain Pintado had a high level of assassin sperm, which shows that he was married to a woman who had multiple sexual partners.”

“Not even close,” said Jack. “At best, it shows that he believed she had multiple sexual partners. I can see where evidence of infidelity might be probative of a wife’s alleged motive to kill her husband. But mere evidence that the victim believed his wife was unfaithful doesn’t add up to any motive on my client’s part to commit murder.”

“Mr. Swyteck may have a point,” said the judge.

Torres grimaced, obviously frustrated. “Judge, could I have a word alone with Mr. Swyteck? I believe we can work this out, lawyer to lawyer.”

“Fine. My bladder’s calling anyway.” He banged his gavel and switched on the microphone. “Court’s in recess,” he announced. “We’ll resume in five minutes.”

The judge made a beeline for the bathroom. The crowd broke into hundreds of small pockets of conversation. Jack signaled to Lindsey and Sofia back at the table, as if to say that all would be okay. Then he and the prosecutor hurried out the side door to a private room.

As soon as the door closed, the prosecutor looked at Jack and said, “I’ll give you one chance to withdraw your objection.”

“And why would I do that?”

“Because one way or another, I’m going to prove that your client was cheating on her husband, and that’s part of the reason she killed him.”

Jack showed no reaction. “I don’t care what you hope to prove. At the moment, all I’m saying is that I’m not going to let you prove it this way.”

“Then it’s her kid who pays.”

“What?”

“My first choice is to use Dr. Vandermeer to prove that Lindsey was cheating on her husband. But if you won’t let me do that, then I’m going to call the kid to the stand. I’m going to ask him how many men he saw come and go from the house when his father wasn’t home.”

“You’re bluffing,” said Jack.

“No, I’m not. So it’s your call, Jack. You can withdraw your objection and let Dr. Vandermeer testify. Or you can stand firm and make me put the boy on the stand. But don’t kid yourself. Before this trial is over, the jury will fully understand that it was you who forced me to sit a ten-year-old child in the witness box so that he could tell the whole world that his mommy is a whore.”

Jack struggled to show no reaction. Several strands of thought were weaving through his head, a tangled mess of conflicting information that seemed to wrap around his brain and choke off all ability to reason. Then he realized it wasn’t thought or reason at all that was clouding the issue. It was emotion, pure and simple-his amorphous feelings for the biological son he’d never met. Meeting Brian for the very first time under circumstances such as these was something he didn’t even want to consider.

“Let me talk to Lindsey,” was all he could say.

At Jack’s request, Judge Garcia stretched the five-minute recess into twenty. Jack watched from across the table as Lindsey massaged her temples, trying to nip a migraine in the bud. Sofia was seated at the short end of the rectangular table, perpendicular to Jack at her left and Lindsey at her right. It was just the three of them in the windowless conference room.

Lindsey’s voice shook with anger as she said, “I can’t believe that bastard would threaten to use my own son against me like that.”

“I can,” said Sofia.

Jack glanced at his cocounsel, as if to say Let me handle this. “Lindsey, as your lawyer, there’s one thing I need to know: What would Brian’s testimony be if the prosecutor called him to the stand?”

She stopped massaging and looked Jack in the eye. “You mean about these strange men coming to our house when Oscar was away?”

“That’s exactly what I mean.”

“It’s absurd. If I were going to cheat on my husband, do you think I would do it in my own house with my son in the next room?”