Translation:Babies are cute.
By that same logic, the sentence 子どもが生まれました doesn't include any indication as to whose child was born, and yet the only answer Duo accepts is "my child was born". It's not wrong to assume that the same would be correct here as well. Consistency would go a long way, sadly these two aren't the only sentences affected by the lack of it....
Look carefully at the sentence of this exercise and your example sentence. I do agree with the first part of your comment though because you're right that leaving it out doesn't mean that it isn't about your own child.
But the difference between your example and the exercise is that you use が where this exercise uses は.
I think context and specific scenarios can cause exceptions in the rule, but generally when は is used in sentences like these it marks something in general. When が is used it marks something more specific.
赤ちゃんはかわいいです means "babies are cute".
赤ちゃんがかわいいです means "my baby is cute" or "the baby is cute".
I'm not a native speaker and I still can't even hold a basic concersation in Japanese, but this is how I have picked it up. If something is not correct or not complete, please leave a reply :)
は is a topic marker, whereas が is a subject marker. So essentially, 赤ちゃんはかわいいです means "as for the baby, it is cute"/"regarding babies, they are cute"; あかちゃんがかわいいです simply has it as the subject of the sentence. The difference is mainly one of emphasis. You're right that が tends to indicate one particular thing to distinguish it from the rest of the group.
That said, I think either could be used to mean "The baby is cute" in this sentence, depending on context.
The base statement, "赤ちゃんはかわいいです" is understandable as, "The baby is cute", "My baby is cute", "Babies are cute", and "Your baby is cute".
Generic English when said referencing any baby ( usually one known to both the speaker and the listener ) is, "The baby is cute". Possession is indicated by previous knowledge of the subject.
Report if any of these translations fail.
Not necessarily. In this language, plurality works quite differently. Nouns without the plural marker ～たち aren't necessarily singular. So 赤ちゃん could either be "a baby", "the baby", "babies" or "the babies", while 赤ちゃんたち could only be either "babies" or "the babies". Additionally, Japanese uses the strategy of the "associative plural", where the plural marker can also carry a meaning of "X and those like it" or "X and their associates" rather than just "more than one X". So, 赤ちゃんたち could also mean "(the) babies and such". This is extraordinarily useful when applied to proper nouns, as something like "Smith, et al." can be translated as スミス君たち. Also, the plural marker can only be affixed to animate nouns, so "tables" is always テーブル. テーブルたち breaks the universe.
True, although looking it up, there is no such thing as 大可愛い, and apparently "adorable" is a translation of かわいい, and the other way around. In this instance, I don't believe that there's too much of a difference between the two, because it's fairly likely that you will hear both when talking about a baby. Maybe for a watch or something, you might be correct, but right now I think is an instance of a fair translation. But I still might be wrong, if I missed something.
Yeah, my knowledge of Japanese is limited, too. Though, maybe the spirit of "adorable" would be best expressed as "hontou ni kawaii," even though going from Japanese to English, that would be better translated as "truly cute."
It's odd. Usually, it seems, there isn't a way to express something specific in Japanese in English, but this may be a rare case of the inverse -- where there's not a Japanese equivalent to an English word.