If siblings are close in age, you are able to raise them all at once.
赤ちゃんのときは大変ですが、育児が短い期間で終わるところはいいと思います。
- I'm sure that it will be difficult when they are still young, but you will finish raising them within a short time period of each other so I think that is a good thing.
When you have your kids close together, it's tough when they are young, but you finish raising all your kids sooner.
この場合、次のような言い方ができますよ。
ーWhen you have your kids close together, it's tough when they are young, but you finish raising all your kids sooner.
「子供たちを（年数的に）近く産むと、小さいうちは大変だが、育児を早く終えられる」
to have one's kids close together で子供を間を空けずに産むことを言えます。
to finish raising kids sooner で「育児をより早く終える」
ご参考まで！
アメリカ合衆国 
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