Medical term; commonly abbreviated as ED in both Japanese and English.
勃起不全の治療薬が開発されている。
Medications for erectile dysfunction are being developed.
彼は勃起不全で悩んでいる。
He is suffering from erectile dysfunction.
勃起不全 is the full clinical Japanese term for erectile dysfunction, while ＥＤ is the common abbreviation used in casual and medical speech alike.
Compound of 勃起 (ぼっき, 'erection') and 不全 (ふぜん, 'insufficiency' or 'dysfunction').