If you want to express that you don't want to have children, you can say any of these sentences:-
1. I don't want to have children.
2. I don't want to have any kids.
Native speakers use the word "kid" informally to mean children.
子どもはほしくないと言いたいなら、以下の文が使えます。
1. I don't want to have children.（子どもはほしくありません）
2. I don't want to have any kids.（子どもはほしくありません）
インフォーマルな場面では、ネイティブスピーカーは"kid"を「子ども」という意味で使います。
If someone asks you why you don't have children, and you want to say it is because you don't want any, you can express this a few different ways. First, you can say, "I just don't want any kids.", which is an informal statement. By using the word, "just", you are expressing that there isn't a specific reason for not wanting to have children; but, you simply don't want any. The word, "kids", is also used, but this is simply an informal word that means, "children".
You can also say, "I don't have children because I don't want any.", which states that the reason why you don't have children is because you don't want to have any.
Finally, you can say, "I don't have the desire to have children.", which states that you don't have a want or a motivation to have children. As a result, you don't want any, so you don't have any. The first sentence should be used in informal situations, such as with friends. The other two sentences can be used in both informal or formal situations. All of these sentences can be used to explain why you don't have children.
誰かにどうして子供がいないかを聞かれたら、欲しくないからと伝えるにはいくつかの言い方があります。
"I just don't want any kids."（ただ子供が欲しくないからだよ）は、カジュアルな表現です。 "just"を使うことで、子供が欲しくない理由は特になく、ただ単に欲しくないからであることを表します。"kids"は、 "children"（子供）を意味するカジュアルな言葉です。
"I don't have children because I don't want any."（子供が欲しくないからいないんだ。）は、子供が欲しくないからいないということを意味します。
"I don't have the desire to have children."（子供が欲しいと思わない。）は、子供を欲しいと思う願望がないことを表します。欲しくないから、いないということです。
はじめの文は、友達のようなカジュアルな場で使うことができます。他の2つは、カジュアルでもフォーマルでも使うことができます。これらは全て、どうして子供がいないのかに対する理由を説明するのに使うことができます。
The two sentences you see provided above are excellent ways to express to your listener that the reason you don't have children is because you don't want children. In the first sentence you will see the term have one's heart set on something. In the second sentence you will see the term bent on having something. Both of these terms mean want. These terms are appropriate for informal settings.
この2つの文は、子供がいない理由は、子供が欲しくないからであることを伝えるフレーズです。
はじめの文では、have one's heart set on something、2つ目の文には、 bent on having somethingというフレーズがあります。どちらも欲しいという意味です。これらはカジュアルな場面で使うことができます。
I do not wish to be a parent at this stage in my life
If you would like to express that you do not want any children, you could use the following phrases:
I would like to be childfree at the moment.
I would not like to be a parent at this stage in my life.
I do not wish to have any children right now.
If someone asks you why you do not have any children you can say “because I simply do not want to have any children”.
You could also use the word “little ones” instead of the word children :)
以下は、子供が欲しくないことを伝えるフレーズです。
I would like to be childfree at the moment.
（今は子供なしがいいです。）
I would not like to be a parent at this stage in my life.
（今は親にはなりたくない。）
I do not wish to have any children right now.
（今は子供が欲しくない。）
誰かがどうして子供が欲しくないか聞いてきたとき、シンプルに“because I simply do not want to have any children”（ただ単に子供が欲しくないからだよ。）と答えることができます。
children（子供）という言葉の代わりに、 “little ones” という言葉も使うことができます。
A common and polite but firm way to say that you don't want to have children is to say that you are not interested in having children. After that, your listener should change the topic. I hope that this helps. :)
"I'm not interested in having children"（子どもを持つことに興味がない）は、子どもは欲しくないと伝える一般的で丁寧、しかしきっぱりとした言い方です。この後、聞き手は話題を変えるはずです。
お役に立てると嬉しいです。
"I don't want children" and "I don't want to have kids"
These expressions state that one does not want to have 'children' or 'kids' this is expressing that they do not want to have their own children and/or be parents.
'Kids' is often the more casual and more frequently used expression when talking about 'children'
"I don't want children" や "I don't want to have kids"は、子供が欲しくないこと、親になりたくないことを表すフレーズです。
'Kids' （子供）は、'children'よりもカジュアルでよく使われる言葉です。
Not every couple has to have children. Some women prefer not to give birth to kids and some men choose not to have them also, by mutual agreement. Children are very expensive and raising a child is the hardest job in the world. It is not uncommon for a couple to be married several years and not have any offspring,
There are a few ways of expressing this. Some women may be embarrassed to say why they don't want to have children and she would simply answer "I simply just don't want to have children". It may be a difficult topic, so I would suggest changing the subject afterwards.
I don't have children because I do not want to have any children.
I do not really want to have children, thus why I still do not have any right now.
If you would like to tell someone that you do not want to have children and that this is why you do not have any yet, you can say something like "I don't have children because I do not want to have any children." or "I do not really want to have children, thus why I still do not have any right now.".
When explaining why you don't have children, you want to explain that it's because you don't want children. In that case, any of the above example statements may fit your scenario.
I dont want children, i want to focus on other things.
I dont want to have kids.
In an informal or formal situation, saying you dont want children or kids is absolutely fine to say as this is due to your own personal reasons.
If you feel like you want to give an explanation as to why but dont want to state your own reason you could just say you want to focus on other things. There isnt a right or wrong reason, this is your own personal reason which doesnt have to be explained to anyone.
Kids, children are mainly used to refer to small children.
All three of these sentences can be used interchangeably to have a similar meaning. Notice in the first two examples that they have the same sentence structure but the second has the additional verb, "to have." This shows us that the verb can be included but it doesn't make the sentence ungrammatical if removed.
The last example is using the phrase, "to be interested in," to describe the desire of liking or wanting something.
This is a very personal question and one can feel quite shy or embarrassed when people ask a question like this because it is personal because some people do not actually want children and another reason would be maybe because the person cannot have children or is struggling to have children. But a simple and straight forward way to answer these people would be by saying;
- I prefer not to have children.
- I do not want kids.
イギリス 
モロッコ 
カナダ 
アメリカ合衆国 
南アフリカ 
アイルランド 
