I'm sorry but I do not follow your logic when it comes to child bearing.
- The mere fact that someone was resident in a Convent does not render them incapable of having children or mean that they were celibate Nuns.
- It does not mean that they were never previously married (in the earthly sense), or that they didn't have a physical relationship that produced children prior to entering a Covent, or indeed after becoming resident in a Convent.
There are historical; and modern day, examples of women entering convents after widowhood or some other significant life event for example, e.g. the birth of an illegitimate child, and also of Convent 'residents' who were not Nuns or training to be so, e.g. expectant single mothers. Similarly, there are documented cases of women leaving convents, marrying and having families.
I would accept that the nature of the religious calling leads to some probability that the majority of Nuns have not borne children, but that is a conclusion (assumption?) rather than a proven Fact.
Should one leap to the same conclusion about a Catholic Priest, i.e. that he had never had children, or another life, or that all Priests, Nuns etc. of whatever religion were invariably 'good' people? Both history and current news suggests very differently.
As far as Civil Unions, Marriages etc. are viewed/reported I would add that most Family History software is sold worldwide and programmers therefore need to be sensitive to a worldwide audience and not just the USA perspective. Legislation and acceptance of same sex marriage does vary greatly across the world; and as I understand it even between different States within the USA. However, it should not be too complex to enable the current Marriage Fact and supporting sentence construction to allow for same sex marriages. The issue that then remains is whether a 'newly' defined fact is needed to record other forms of union such as a Civil Partnership (which may in some countries apply to both same sex and heterosexual couples) or whatever term is recognised in different countries; or whether such variants can be added as options to the standard Marriage event with an appropriate sentence construct, which should make it easier to assure the transferability of such facts between software products using the existing GEDCOM standard.