Why did Allah use the phrase "He begets not" (لم يلد), even though it is the female who gives birth, and some Christians interpret that to mean Allah is female?

Wise people among the Children of Adam have not described Allah Almighty as having masculinity or femininity. Rather, Sheikh al-Islam Ibn Taymiyyah said that affirming a son for Allah was not a physical birth, but rather a spiritual and abstract one.

Allah Almighty is not described with masculinity or femininity. Rather, He is the One, the Unique, the Self-Sufficient. Allah revealed Surat Al-Ikhlas, which describes His essence and attributes. Thus, He exalted and sanctified Himself above origins, offspring, peers, and likenesses. He is unlike creatures, from whom Allah created pairs. The purpose of Surat Al-Ikhlas is to negate origins, offspring, and peers from Allah, distinguishing Him from creatures. So, He denied having origins, offspring, and peers, which are the sum of what is attributed to a creature. For everything among creatures must have an origin, or an offspring, or a peer.

Ibn Aqil said that negating a son from Allah is not because He is male and not female, but because fragmentation and division are impossible for Him. The intention is that no one has separated from Him, and He has not separated from anyone.