I am a proffessor in an MFT program.
One of my students has a client of 14 that got pregnant
with a men of 20 , it was consensual sex.
I thought this was a mandatory reportable situation, my student and supervisor said no.

Under New Mexico law, a 14 year old legally can NOT have consensual sex. If an adult has sex with a 14 year old in New Mexico, they are committing a crime. The 20 year old has violated New Mexico law:

30-9-11 Criminal Sexual Penetration
F. Criminal sexual penetration in the fourth degree consists of all criminal sexual penetration:
(1)not defined in Subsections C through E of this section perpetrated on a child thirteen to sixteen years of age when the perpetrator is at least eighteen years of age and is at least four years older than the child and not the spouse of that child; or
(2) perpetrated on a child thirteen to eighteen years of age when the perpetrator, who is a licensed school employee, an unlicensed school employee, a school contract employee, a school health service provider or a school volunteer, and who is at least eighteen years of age and is at least four years older than the child and not the spouse of that child, learns while performing services in or for a school that the child is a student in a school.
Whoever commits criminal sexual penetration in the fourth degree is guilty of a fourth degree felony.

Reporting laws are outlined in the following Statutes.
§ 27-7-30 Duty to Report
§ 30-47-9 Reporting Requirements
§ 28-17-9 Referrals

You will find all New Mexico Statutes at http://legis.state.nm.us/lcs/