It is a little blurry but I think I can see a bit of creamy/white opaque pee? Quite near the tail and this suggests to nme this is a wee girl Ems. A wee boy would be further from the tail than that... Can you see the hint of nipples at all?
The best thing you can do is check every day and try to hold two at once comparing their genitalia side by side. You will be a pro at it by the time they are all weaned