Need To Confirm The Sex of This 5 Week Old

[cubfan]

We got a surprise pregnant guinea that had 3 healthy babies, 2 that we could clearly tell were females which have been rehomed, and this guy (i think guy?)
Any other opinions would be very helpful. The baby has been isolated until I can get a confirmed sex on it. I have tried putting gentle pressure above the opening but have not been able to get any sign of a guinea pig penis to show. Thank you for any and all help.

 

[cubfan]

Is there a hard ridge on the area above?

There is what feels like a hard ridge, which i guess indicates male but without more evidence I wasnt too sure i should be confident in that. The 2 girls in the litter were very easy to tell, this guy (or girl) is harder for me to properly tell. I feel the ridge and it has a much larger spot at the top of the opening unlike the females had, im leaning male but what are your thoughts. I figured the more opinions i could get the better. If hes a he then i will be able to introduce him to my boys and keep him, the girls have all been rehomed to a nice family.

 

[Soecara]

Personally the pup looks very female to me. If you are feeling a ridge place your finger at the top of the ridge (the point furthest away from the genitals), then gently but firmly roll your finger down. If the pup is indeed a male you should be able to feel the ridge move and begin to expose a penis.

Here are some photos of mine for comparison of young pups with their genitals gently parted, which might also help.

This is a female


This is a male