This isn't about men v. women, it's about understanding mental health problems and ensuring that everyone can access the help they need.
I totally agree @LorelaiVictoriaGilmore but diagnosing men with PND isn't going to get them the treatment they need because the treatment for PND and the treatment for situational depression are not the same.
As an example, my DH went to his GP first when he was struggling after my DD's birth. He was prescribed Prozac and struggled through the side effects only to find it wasn't really helpful. I mentioned it to my specialist mental health team who explained that SSRIs aren't really appropriate in the case of situational depression because there's no chemical imbalance to be straightened out, just someone in an extremely difficult situation who needs support getting through it. They took him on as a patient instead, got him off the Prozac and gave him CBT, taking therapy and occupational therapy. It made all the difference.
Whereas for me, with actual PND, Prozac and Propranalol plus coming off the Pill made all the difference. I didn't need talking therapy. I had no problems with the situation. I wasn't suffering after the birth, I wasn't struggling to adjust to my new life - all those things were totally fine once I was on the right medication regime and the hormone imbalance had been addressed.
I'm not trying to take anything away from men or non-birthing parents who are struggling with their mental health after having a baby. Nor am I saying that women who have situational depression or PTSD after giving birth are suffering any less than women with PND. I just think it's important that people get the correct diagnosis in order to access the right treatment.