Yes, easily.
The oldest had a swollen, squashed face and dark hair that got shaved over one ear and she was over 10 pounds. Easily the biggest baby in the NICU! I was actually kind of sad when the hair grew in after a few months, I was so used to it.
Younger kid had red curls and a wonky left eye (it doesn’t go left–though actually I guess I didn’t notice that for about 3 days).
Both just looked like themselves; I could have picked them out of a crowd.
Took a couple of days. Combination of bleary-eyed new motherhood and not wearing contact lenses (I can’t see all that well with glasses).
It helped that my sons were usually the only redheads in the nursery.
After that couple of days, though, I knew them well enough, even without corrective lenses. And the feel of them.
By the time they were walking, I knew the sound of their footsteps (they are distinctive), the shape of their gait (even when they were in uniform, standing bored out in left field), their distinctive mannerisms.
Is this on family resemblance? I mean, I know people say their kids look like this relative or that but I can never see it. And I’ve seen baby pictures of myself and my brother and cousins and to me at that age, there’s no resemblance at all.
Anyway, I hope it is different when it’s your kid for the sake of my hypothetical babies. To me they all look so similar.
So is telling (fraternal) twins apart not a huge issue for parents? Or does it depend?
IME babies are as easy to tell apart form each other as adults are - that is, some look unfeasibly similar to each other (I’ve known a couple of people who had unrelated “twins” running round in the same community, who were constantly being mistaken for them) but in general once you’ve got a good look at them it’s not a problem to recognise them again. I’d be confident of recognising not only my own children again, but most of my friends’ too, after one exposure.
Having said that … I have had the experience of coming into a room where a little blonde toddler was running around and thinking “How did my son get over there so quickl… oh, wait, I’m still carrying him!”. But that was only a passing lapse.
Ours had more hair than any other baby out there, and she was so beautiful that the nurses moved her crib to the window of the baby room even when no one was coming to visit. Plus my wife’s roommate, who did commercials, recommended that my wife take her to New York to audition.
She did, but my daughter didn’t have the right personality then. It took her a full ten years to get an acting job. 
My daughter was born in a small clinic and was the only child there. On top of that she was almost 12 lbs at birth. But even with these things absent I would have recognized her within minutes. She was very pink, looked like an Eskimo, was very hairy with a headfull of long hair and had my husband’s features.
My son looks a lot like my wife and my daughter looks a lot like me, and they did so even when they were newborns.
Of course. My daughter was 4 weeks early when she was born and she was in the nursery quite a bit - it was easy to pick her out. My son looked like me as a baby. I never thought about it - they were so distinctively mine.
I don’t have kids, but one thing I have noticed is how overwhelmingly interesting your own child is. This is beyond any normal experience of something being interesting. You pay that much attention to anything, you’re going to learn to recognize it quickly. Certainly within 4 weeks.
I had no problem doing so. He was born at over 9 lbs, and had a full head of what looked like black hair that has since lightened somewhat. His skin tone was pale but not very reddish so to me he was easily identifiable.
I see hundreds, maybe thousands, of babies every year. They not only all look different, but they all sound a little different, too. They come in fat, slim, hairy, bald, big, small, long, short, etc.
(Although, my friend did have some very identical identical twins that were very difficult to differentiate for a while- LOL!)
This is only my experience of course, but la belle fille was born in the early evening. I held her and cuddled her but then she was taken away to be evaluated (small and slightly jaundiced) and I was taken to recovery. Much later that night, I (gingerly) got out of bed and began shuffling down to the neonatal unit. Far down the hall, a nurse was pulling two of those wheeled cribs they transport the infants in. I heard a tiny thin wail and instantly recognized it as la belle fille’s “voice.” The nurse was bringing her to my room so she could stay with me.
I caved and chose the second option, but I’m pretty sure I could have recognised her easily in a room full of babies. What are the odds of two of them looking exactly like my brother did as a baby?
My oldest is adopted and Korean. He was easy to pick out from the majority of kids we knew until he was six or so. When he was four we took him to an event for Korean adoptees, and not that I couldn’t pick my son out from a crowd, but it became a lot harder with 200 kids running around that looked a LOT more like him. One of his very good friends is Hmong and they play sports together - in a baseball uniform from a distance I have to look at the numbers (in the face they don’t look that much alike - with a ball cap on, the same haircut, the same skintone, the same build…)
But both had/have unusual birthmarks that if it got down to “its one of these” would let me pick it out.
Also, babies recognize and prefer their mother’s voice at birth - from hearing it the womb. (and my son figured out who Mom and Dad were in a week). So even if you wouldn’t recognize them - they are the ones that turn their head to hear you (that changes, by the time they are six they apparently become deaf to the sound of their mother’s voice).
I once had trouble picking out my grandmother from a recreation room in the old folks home/hospital. It was a big room, lots of tables and around all of the tables sat old ladies nodding off. All of them wore the same old lady dresses and all of them had visited the same hairdresser that morning, where they had been permed like on a conveyor belt.
I did this experiment in real life and the answer is no, not really. My daughters started day care at 8 weeks old and I did the afternoon pickups. Their day care center is pretty big and the kids are nearly all white and look pretty similar. The infant room had six or so babies at a time and I had to let the day care workers give me cues which ones mine were when I came to pick them up and I almost made a mistake a couple of times. I could have figured it out eventually through careful study so it wasn’t like I was ever going to take the wrong child home but I couldn’t really recognize them instantly from across the room on short notice either especially when they were bundled with hats on.
Both of my babies stood out. My children always stood out to me in any setting. This may be a Mom thing? From the moment they were layed on my chest I fell in love with every feature on their face.
My son went to daycare at an inner city daycare when I was in technical school. He sometimes brings out the class picture now that he is grown and we both laugh. Talk about standing out he was the only white toddler in the picture. It was a class of 20 or so and it is startling. This was back in the 80’s and he was so well cared for by the loving teachers. I had to pull him out because of the drive by shooting. I was also almost mugged picking him up but once inside he was loved and well taken care of.
Not a hypothetical for me - the hospital nursery did not label bassinets with names, and one of my responsibilities was to identify which one was ours to family and friends. It wasn’t really a problem even at a distance.
It’s very likely that, given the opportunity to get close enough, 100% of the motherswould recognize their babies from smell alone. It takes just 10 minutes of smelling your newborn to be able to distinguish its smell from other infants. Even just touching their hands, both mothers and fathers were able to identify their own baby (out of three) with twice the accuracy one would expect by chance.
Even"most" non-mother women were able to distinguish a newborn from others after an hour of holding it. (I don’t have a subscription to that site, so I can’t get the full text to see how many “most” is.)
For myself, I wasn’t allowed to smell or touch my baby for a few days after her birth because she was behind plastic, so I had to go on visual cues alone. And it was not a problem at all. I can’t tell you why my alien looking preemie looked different from every other alien looking preemie in the NICU, but she sure did.
I would have no problem recognizing either of my children within minutes of their birth if they were placed in a room with a bunch of similar looking newborns. My husband, however, freely admitted he had to look at the name tags on the bassinets each time he went into the hospital nursery.