Assalamualaikum,
I also got stuck when I found the fact in the verse for the first time. But I was sure that the Quran is true, my understanding may be false. After 2 hours, an interesting thought entered my mind. Now, I am sharing it with you.
You may know that Muhammad (ﷺ) was a shepherd in his early life. So, he undoubtedly knew that male cattle don't produce milk. So, if he wrote Quran (as the critics say), he would use the feminine word here. But why not? Because he didn't write it.
First, I'd like to mention some information:
- Feminine words only mean Feminine. But masculine words can mean Common(especially when plural) or Neuter gender as well. For example, in Surah Al-Hashr - 59:22 (please notice the part - "Knower of the seen and unseen" in this verse also, I will use it later) and many other places, "he" is used as a pronoun to express "Allah". But Allah is neither masculine nor feminine.
- In Arabic, most of the verbs have the same form to express both present and future tenses.
Now come to the point. In fact, all mammals, both male and female, have breast tissues. But in males, these become inactive due to the absence of some hormones. So, male cattle have all the necessary organs to produce milk but at an inactive stage. But, male lactation can be possible under certain circumstances. Even male goats are also found to lactate on occasion. All may not agree with it. So, the example of Dayak Fruit Bats may be suitable for them (they are not cattle. So, the verse doesn't say about them. I'm giving just an example to prove that male lactation is possible in mammals as they are mammals). In their bodies, the breast tissues don't get disabled.
So, it may not be impossible in near future that Genetic Engineers will remove the cause of making breast tissues inactive in male cattle, even bulls, and make them lactate naturally with the grace of Allah. Then if Allah used بُطُوْنِهَا, critics would say, "Muhammad didn't know that we would change the DNA sequence and make the males lactate. So, he used feminine verb". Even they would deny the credit of Allah according to Al-Quran behind this process in males to criticize Islam.
But Allah knows the unseen, knows the future. So, he didn't leave the opportunity for the critics. When genetic engineers will be able to do this with the grace of Allah, In-Sha-Allah we will feel proud of another miracle in Al-Quran.
Now critics may raise another question that why did Allah use the present tense? Don't worry, in most of the Arabic verbs, forms for present and future tenses are the same (known as Imperfect tense).
Subhanallah, from the same verse some people try to find mistakes whereas some others find miracles. Allah reveals his signs to the intellectuals.
If you find it helpful, please inspire me by an upvote.
May Allah forgive me if I make any mistakes.
Allah knows best.