Rearrange the following four sentences (A), (B), (C) and (D) in the proper sequence to form a coherent paragraph.

(A) This is probably one of the reasons why the number of women and men remain roughly equal in most societies.
(B) Fortunately or unfortunately, individual couples cannot really be concerned about this overall ‘error’.
(C) Population growth then can be considered the error of this central process.
(D) Purely at the human level, it appears that most couples like to have at least one living daughter and one living son when they are in the middle ages.