1.Killing members of the group;
1-1.5 million Armenians were killed. This isn't denied; the Turks just say that it was due to their acts in the war, not a concentrated effort.
2.Causing serious bodily or mental harm to members of the group;
This was present throughout the forced relocations in which much of the killing took place.
3.Deliberately inflicting on the group conditions of life calculated to bring about its physical destruction in whole or in part;
The stated goal of the relocation was to push the Armenians out of the Ottoman Empire, via forced deportation, killing, and rape, which was systematic in nature.
4.Imposing measures intended to prevent births within the group;
In addition to the previous criterion's answer, the men were separated from the women and children early in the relocations. Men also accounted for the majority of the dead.
5.Forcibly transferring children of the group to another group.
Additionally, women and children were sold into slavery and forced marriages.
These were all done deliberately, as attested via eyewitness accounts in "The Armenian Genocide: an interpretation"
I believe that leaves only the post factum argument.
Article 11, paragraph 2 of the Universal Declaration of Human Rights
provides that no person be held guilty of any criminal law that did
not exist at the time of offence nor suffer any penalty heavier than
what existed at the time of offence. It does however permit
application of either domestic or international law.
Very similar provisions are found in Article 15, paragraph 1 of the
International Covenant on Civil and Political Rights, replacing the
term "penal offence" with "criminal offence". It also adds that if a
lighter penalty is provided for after the offence occurs, that lighter
penalty shall apply retroactively. Paragraph 2 adds a provision that
paragraph 1 does not prevent trying and punishing for an act that was
criminal according to the general principles of law recognized by the
community of nations. Specifically addressing the use of the death
penalty, article 6, paragraph 2 provides in relevant part that a death
sentence may only be imposed "...for the most serious crimes in
accordance with the law in force at the time of the commission of the
So, by international law, it is what is currently known as a genocide but cannot be punished as such, because there was no law for the crime itself at the time and as a European nation, Turkey is subject to the above because:
Effectively all European states (except Belarus), including all
European Union and European Economic Area states, are bound by the
European Convention on Human Rights. Article 7 of the convention
mirrors the language of both paragraphs of Article 15 of the
International Covenant on Political and Civil Rights, with the
exception that it does not include that a subsequent lighter penalty
So... yes and no.