FITMI - First In Treating Male Infertility

Inclusion Criterias: * Infertile men ≥ 18 years and \< 60 years of age * Sperm concentration ≤ 20 million pr. mL * Serum AMH levels ≥38 pmol/L. * The participants must have appropriate Danish or English language skills and give written informed consent. Exclusion Criterias: * Chronic diseases, defined as diagnosis where signs, symptoms, and treatment imply an expected long duration and lack of a cure, such as diabetes mellitus, metabolism disorders, osteoporosis, colitis, etc. * Sperm concentration \<2 million pr. mL * Men with current or previous malignancies, or at potential risk of testicular cancer after baseline examination and ultrasound will be excluded. * Men with hypocalcemia at baseline, defined as ionized calcium of \< 1,18 mmol/L or albumin corrected calcium \< 2,17 mmol/L or total calcium \< 2.14 mmol/L * Serum vitamin D (25OHD) levels \< 25 nmol/L * eGFR \< 60 mL/min/1,73 m2 * Insufficient dental status * Vasectomy * Semen volume \< 0.9 mL * Hypersensitivity to latex, Denosumab, or to any of the excipients (acetic acid, sodium hydroxide, Sorbitol (E420), Polysorbate 20) will be excluded.