It is wrong according not only to the Church but according to God. God designed human sexuality to work in a particular way. Medical technology can be used to assist the natural functioning of that process (e.g., surgery could be used to repair fallopian or vas deferens tubes), but medical technology cannot be used morally to replace the reproductive process that God designed. Indeed, nothing can replace the process morally (that is why homosexual behavior, for example, is intrinsically immoral).
The MicroSort process involves several stages that unambiguously interfere with God’s design for human sexuality. The sperm must be collected, sorted outside of the body, and then either in vitro fertilization or artificial insemination must be done. All of these—including the way the sperm collection is normally done—are intrinsically contrary to the way God has set up human reproduction. The Micro-Sort method thus constitutes a replacement of natural and not the assistance of nature and is intrinsically gravely sinful.
There may be, however, something natural that can be done in your situation. For further assistance, contact the National Catholic Bioethics Center, 159 Washington Street, Boston, Massachusetts 02135, (617) 787-1900, www.ncbcenter.org.