There have been many studies over the years that point out that Bhik(kh/s)uni ordination is perfectly legal with regards to the Vinaya. Although there are still groups and governments that contest this conclusion, I feel this is something that will be more and more accepted over time.
There is however another authority that goes above the Vinaya that would apply in many Western countries, especially the countries where men and women (and all other genders) are 100% equal for the law.
That local laws prevail over the Vinaya we see in many different areas. In building a monastery or kuti for instance, it is quite normal that measurements and details as outlined in the Khandhakas are in violation with local building regulations. In that case, local building regulations take precedence.
Here in Belgium, the Law of May 10, 2007 to combat discrimination between women and men prohibits any form of discrimination (or difference) based on sex. Discrimination on the basis of gender reassignment, gender identity and gender expression is equated with this. Both direct, and indirect discrimination, ordering discrimination, harassment and sexual harassment are explicitly prohibited.
The equating of a direct distinction on the grounds of gender reassignment with a direct distinction on the grounds of sex (art. 4 §2 of the Act), is in accordance with the European Directive 2006/54/EC. This Directive follows a judgment of the Court of Justice of the European Communities and provides that the scope of the principle of equal treatment between men and women cannot be limited to the prohibition of discrimination related to belonging to one or the other sex, and that the principle also applies to discrimination based on the gender reassignment of a person.
The equating of a direct distinction based on gender identity or gender expression with a direct distinction based on sex (Art. 4 § 3 of the Law) was established by the Law of May 22, 2014. Its objective is to extend protection against discrimination to all transgender persons and not only to provide protection to those who foresee, are undergoing or have undergone treatment to change gender.
To summarize: people of all genders are equal for the law and no difference is to be made between them whatsoever.
These local laws are in direct opposition with certain parts of the Vinaya, especially the differences between Bhikkhunī and Bhikkhu ordinations. I will limit my argument here to this difference but these local laws also underline the conclusion I drew in my work on transgender ordination; namely that transgender people should be able to ordain according to their gender-identity.
We see two main differences between the ordination procedures for Bhikkhus and Bhikkhunīs. Firstly, there are the “Antarayika-dhamma”, which means impediments or obstacles to ordination. It concerns a list of 23 questions for Bhikkhunīs and 13 questions for Bhikkhus posed to the ordination candidate to ascertain whether or not they are eligible to take higher ordination.
Secondly, Bhikkhunīs need to have a dual ordination, before both Saṅghas. Bhikkhus only need to have ordination before the Bhikkhu Saṅgha. This difference is actually historically grown out of the first difference because some women felt embarrassed to answer the Antarayika Dhammas before the Bhikkhu Saṅgha.
Some of these questions for Bhikkhunīs that the Bhikkhus do not have are problematic:
Do you lack genitals?
Are your genitals incomplete?
Are you without menstruation?
Do you menstruate continuously?
Do you always wear a menstruation pad?
Are you incontinent?
Do you have genital prolapse?
Do you lack sexual organs?
Are you manlike?
Do you have fistula?
With regards to Belgian law, it is not just this obvious difference between men and women that is problematic, but also that the questions asked are discriminatory, private and degrading.
History of Bhikkhunī Khandhaka
The history of this difference is also interesting. Several scholars pointed out that the language used in the Bhikkhunī Khandhaka is more in line with the language used by the Jain. It is also fairly widely accepted that the Bhikkhunī Khandhaka is a later addition to the Khandhakas. I refer to Bhante Sujato’s excellent study on this topic and won’t go into detail about that here.
Ajahn @Brahmali pointed out that the Saṅgha might have established these rules in order to prevent them getting inundated with candidates seeking ordination for the wrong reasons, namely because they were unable to marry because bearing children was very important in ancient India. Women with genital medical problems might have been considered outcasts and in order to survive and for protection might have sought refuge in the Saṅgha.
Another possibility might be simply that the procedures laid out for Bhikkhunīs in the Bhikkhunī Khandhaka is the Jain Bhikkhunī ordination procedure (probably merged with the Bhikkhu ordination procedure). The obsession with bodily perfection, especially in the Digambara sect, would make ordination impossible for any woman with any of the above imperfections. Moreover, Jain nuns are subordinate to monks and are not permitted to handle any of the scriptures. In other words: the ordination procedure for women is laid down by monks. More research is needed to come to any definite conclusions with regards to this hypothesis.
There might be some truth in both standpoints and it might explain the difference in Antarayika Dhammas. However, none of the historical reasons for these Antarayika Dhammas still apply today in western countries.
I think it is also important here to point out that the Antarayika Dhammas at least in the Theravada tradition do not prohibit ordination, but they do in the Chinese Vinayas. Still, the fact that these questions are asked is in any case clearly against the law.
As far as I know, no Bhik(kh/s)uni ordination has yet happened in Belgium (although I am not 100% certain of the Mahayana traditions and this is something I’m trying to find out). It is however important for the future to look into this, especially now Buddhism is on the verge of being recognized in Belgium. The Buddhist Union of Belgium is very supportive of doing more research into this, also with a wider scope of future ordinations with EU countries. I have also been in contact with the Institute for Equality of Belgium and are awaiting their findings. I hope that we can make necessary changes within Europe to allow a more equal treatment of all genders within Buddhist monasticism. Right now the barrier for ordination for women and transgender people is far higher than for men. I feel the time is right to start making some changes.
Just as we are able to adapt Khandhaka rules to be in line with local laws with regards to building, we can easily change the Bhikkhunī ordination procedure to be in line with local laws on gender equality by omitting the offending 10 questions.
Bhante @Sujato already suggested that ordination of Bhikkhus could be done in front of both Saṅghas so as to make this part of the procedures more equal. Personally I would rather see ordination done by a Saṅgha of mendicants from all genders rather than keep the binary split, but I think the Buddhist world is probably not ready for such a radical shift yet.