Title: Critical Period
Author: mirage
Feedback e-mail: miragesdream@gmx.net
Fandom: CSI
Pairing: Sara Sidle / Sofia Curtis
Spoiler: only for Nesting doll.
Summary: another lesson in neuroscience.

Disclaimer: CSI and its characters are the property of Jerry Bruckheimer and CBS.

Note: this is a sequel to 'Oxytocin'. I know sequels are never as good as the first story, so blame it on the books I'm reading. They give me all these ideas.

Note2: The quotes are from Harry Chugani, brain development: PET studies of normal maturation and social deprivation

Critical Period
by mirage

"Do you miss me?" At the question Sara looked up from her forensic journal, gazing at the only other person in the break room.

With her back to the brunette Sofia was standing at the coffee machine, adding milk to her coffee and stirring the two liquids. Nothing indicated that she had said anything at all.

First Sara thought about ignoring the question, like they were ignoring each other lately, barely able to stay in the same room. The wounds were still too fresh, the yelling still too loud in their ears for the cliché of lesbian-exes being lifelong friends to even be up to consideration.

Sara remembered the first time Sofia had asked her that particular question. Back then the answer was simple.

She had taken off the day of Sofia's return, her request surprising Grissom, but to Sara's relief he hadn't commented on it. Not two hours later she had been standing at the McCarran International Airport, searching the crowd for the blonde detective.

It was an easy task, the blonde outstanding in every way. Her long blonde hair glistered in the sun, her eyes were hidden behind the over-large black sunglasses and she wore one of her tight fitting shirts, her whole outfit signalizing "don't mess up with me".

In Sara it just elicited longing and desire.

They hugged each other, standing a little bit too close for a little too long. But other than that, they showed no sign of 'inappropriate' affection in public before Sara grabbed Sofia's bag, ignoring the blonde's protest that she was capable of carrying it herself.

Their first proper welcome was in the small privacy of Sara's Denali after which Sofia asked, "did you miss me?" as if the small making out session wasn't indication enough. Sofia was the type of person who wasn't satisfied with the action, she wanted the words as well.

They were different in many aspects.

"Yes." Sara answered without hesitation. She wet her lips when Sofia's hand slowly wandered from her knee to further regions.

Sofia smiled smugly. "How much?" she asked, stopping the movement of her hand before she started something that was even less appropriate at the very public car park of an airport.

"Enough to ask for a day off." Sara whispered. She didn't know if she should be offended or amused when she saw Sofia's look of sheer surprise. But at least the blonde recovered quickly, on her face emerging the biggest grin ever. "Your apartment. It's closer," she commanded and Sara was just as eager to follow the order.

Back than life had been good and simple.

But nothing ever stayed the same and slowly, barley recognizable, their relationship had changed. It probably all began on a slow afternoon that found them snuggled against each other on Sofia's comfortable couch, watching the discovery channel. At least Sara had watched the documentary while Sofia was content with combing through Sara's hair and reading a magazine.

The documentary that was on, started in the eighties following the fate of Romanian orphans, who had to live under unbearable circumstances in orphanages. Neglected because the state couldn't afford enough staff, they were forced to stay in their cribs, human contact limited to handing out food.

Back then the pictures had touched many people, causing a lot of American couples to adopt. But their suffering didn't stop with the adoption and it seemed that all the love their new parents gave them wasn't enough to make up for the first years of their lives. Insecure attachment, behavior problems, social problems, aggressive and delinquent behavior, thoughts and attention problems and psychological problems like anxiousness and depression were just a few symptoms.

Sofia even put her magazine aside to pull Sara closer, holding her tightly against her chest. "Poor kids," She said and Sara nodded in agreement, still mesmerized by their dark and expressionless eyes.

"The longer you live without a stable, supportive family, the more the risk for emotional and conduct problems," a woman explained, the fade-in identifying her as a psychologist named Megan Gunnar from University of Minnesota and for the split of a second Sara felt the same panic that sometimes overwhelmed her when she was supposed to sleep, but instead was listening to her fast-beating heart, feeling as powerless and overwhelmed with fear as she had as a child.

Their faces were haunting her in her sleep and Sofia pulled her closer, mumbling sweet nothingness into her ear. She knew how domestic abuse got to her girlfriend, the reason she didn't know and had never dared to ask.

"PET studies showed abnormal function in brain regions associated with emotion, memory and executive functions. These regions are strongly interconnected and many are damaged with prolonged stress."

Growing up in an household where fights, yelling and trips to the hospital were routine, definitely classified as prolonged stress.

Sara could fight psychological problems, she always had been a fighter. But how was she supposed to overcome a brain damage?

No willpower could do that.

"I love you." Sofia whispered when she thought her lover was asleep and Sara kept her eyes close, pretending to sleep even though she whished she could turn around and tell Sofia that she loved her too, but how could she when she wasn't even sure anymore she was capable of this emotion.

"In development there are critical periods in which certain skills can be acquired with greater ease than in later times. Some 'critical periods' are short, e.g., early social interactions, the deprivation of which can lead to attachment difficulties and psychopathology."

Sara was watching the scene in the interrogation room through the one-way mirror as Brass interviewed a 22 year old murderer who didn't even show any sign of remorse. Derek Koonz had killed the owner of the small Deli in cold blood, his loot not more than 50 dollars. He was guilty, the evidence was clear, they even had the murder on tape from the surveillance camera and still he had good chances to get a mild sentence. Abused childhood, half of his life spent in foster care and on the streets that always impressed the jury.

In her it only stirred the anger.

The door to the small room opened and without turning around Sara knew that Sofia had joined her. She felt her eyes upon her, knowing that the blonde once again wanted to talk about their relationship and still, she refused to acknowledge her. She didn't want to see the hurt and sadness in her eyes, knowing that she had put them there.

"Sara, we need to talk." Sofia tried to sound confident and strong, but Sara knew better.

They had tried the talking many times before. Normally it ended in yelling and accusations on both sides.

"Do you believe in a murder gene?" she asked instead.

Sara didn't need to turn around to know that Sofia stared at her in disbelief. A deep breath and every emotion vanished from Sofia's voice. "Tell me when you're ready to talk," she said before she left the room, leaving Sara behind, her question unanswered.

That was the end.

"A negative environment will strengthen the expression of negative genetic behavioral traits."

Sara once had asked Grissom if he believed in a murder gene and he had answered her that he didn't, but deep down she always knew that the friend and not the scientist had answered her.

What if her genes held more power over her than she ever wanted to admit?

She couldn't do that to another person, especially not Sofia.

Sofia.

She was still waiting for an answer.

The blonde hat turned around, now leaning against the counter, but refused to look at Sara. Instead she looked down at her coffee, still stirring the liquid. It was probably cold by now.

How could she explain that she didn't know? That she didn't trust herself in anything anymore. She had always turned to science when she had nothing else to believe in and it had given her the support she needed, stabilized her. And now it was the thing that scared her most that made her questioning everything she had achieved.

It was the reason she had lost Sofia.

"I wish I knew."

Sofia just nodded, not the slightest surprised by the brunette's answer. When she looked up her eyes were filled with unreadable emotions. "Tell me when you know."

"It's unknown how much genes or prenatal environment might influence recovery from early brain disturbance. Many of these kids have a remarkable capacity to turn around when they're adopted."

Sometimes when lying alone in her bed, threatened to be overwhelmed by tears, Sara prayed to a god, she had last believed in with four that the first, but few happy years of her life had been enough.

She knew as she watched Sofia's retreating form that today was one of these days.

The end