Semen transfer by innocent means?

[Quartz]

Can knowledgeable Dopers elaborate on how semen can transfer to a girl’s underwear by innocent means?

The issue is this case where the convicted <censored> tried to blame the parents.

@BBC

Despite the mobile phone evidence, the boy’s barristers had suggested Viktorija’s parents may have played a part in her death after it emerged microscopic traces of her stepfather’s semen were found in her underwear.

But the pair were eliminated from police inquiries at an early stage, and forensic experts suggested the transfer of her stepfather’s DNA was via innocent means.

I’m guessing that the likely explanation is simply that garments were laundered together: with lower-temperature washes being a thing these days, biological material is more likely to survive. But that’s a guess. Could more knowledgeable Dopers fight my ignorance?

[markn_1]

I am by no means knowledgeable about this topic, but one case I can imagine is the man has sex or masturbates, gets dressed without bathing, and sits in a chair which transfers a microscopic amount of semen to the chair. Then the girl later sits in the chair. Or, more directly, the girl sits on her parents bed.

[doreen]

At one point in the article, it refers to the stepfather’s semen. At another point, it refers to his DNA. All of the other articles I’ve refer to solely DNA- and there is a difference. It’s hard to imagine innocent explanations for a semen transfer that aren’t somewhat weird involving semen being identifiable after going through the laundry or sitting on a bed at a close enough point in time. But DNA - much easier to explain. I actually read something that referred to the following experiment yesterday

In one of his lab’s experiments, for instance, volunteers sat at a table and shared a jug of juice. After 20 minutes of chatting and sipping, swabs were deployed on their hands, the chairs, the table, the jug, and the juice glasses, then tested for genetic material. Although the volunteers never touched each other, 50 percent wound up with another’s DNA on their hand. A third of the glasses bore the DNA of volunteers who did not touch or drink from them.

So it seems the transfer could have happened if the stepfather even touched the underwear - or if someone/something the stepfather touched in turn touched the underwear. For example, if mom had stepfather’s DNA on her hands and folded the laundry.

[Joey_P]

I’m gonna guess he jerked off in a sock or some other piece of clothing or on a towel. His laundry and her’s were co-mingled in a hamper and their was some transfer of biological material.

[Quartz]

@doreen

I actually read something that referred to the following experiment yesterday

Interesting!

So it seems the transfer could have happened if the stepfather even touched the underwear - or if someone/something the stepfather touched in turn touched the underwear. For example, if mom had stepfather’s DNA on her hands and folded the laundry.

Yes - it’s just as likely that the stepfather folded the laundry these days.

[ZonexandScout]

@Joey_P

I’m gonna guess he jerked off in a sock or some other piece of clothing or on a towel. His laundry and her’s were co-mingled in a hamper and their was some transfer of biological material.

Not that there’s anything wrong with jerking off in a sock…

It might be much simpler to assume that semen was deposited on the mother’s or stepfather’s underwear due to their engaging in intercourse. It would also most likely be found on their sheets, hand towels, and so forth. How it got transferred is still up for grabs (no pun intended).

[Gatopescado]

Why did I read this? :smack:

[Littleman]

Persistence of DNA from laundered semen stains: Implications for child sex...

https://www.google.com/url?sa=t&source=web&rct=j&url=https://www.stmaryscentre.org/application/files/9514/7697/8318/stmaryspresentation21.1.16.pdf&ved=2ahUKEwiCm6usvtLgAhUJOawKHVpYD9sQFjAOegQIChAB&usg=AOvVaw2sMYu8RKl89N6Ib_266joT&cshid=1550946731184

Sperm transfer in washing
machine
• Child alleges step father has been having vaginal
intercourse with her
• All underwear has been washed
• AP test for 10 mins – negative
• Extracted crotch area – trace semen – profile matches S
From drainage? Crime related???
• Extracted other areas of the knickers – trace semen –
profile matches S
Unable to attribute trace of semen to criminal activity
So essentially looks like if amounts and/or locations are not consistent with sexual contact then innocent means are probable, or vice versa.

They’re looking at a number of factors since microscopic evidence gets around really well.

Eg; finding trace kanine fecal matter on your shirt doesn’t mean a dog took a shit there or that you touched your dogs butthole, but if it’s found in an oblong spot on the floor and there’s a concentration higher than other areas of the floor then well, a dog probably shit there.

[Beckdawrek]

@Gatopescado

Why did I read this? :smack:

I’m with you on this one. Gah!

[Tim_R.Mortiss]

It could have been transmitted by a bullet.