What are the recommended steps for a 50‑year‑old man without children to achieve biological paternity?

Achieving Biological Paternity at Age 50

A 50-year-old man seeking biological paternity should first undergo concurrent fertility evaluation with his female partner, including comprehensive reproductive history, physical examination, and at least one semen analysis, followed by referral to a male reproductive specialist if abnormalities are detected. 1, 2

Initial Concurrent Evaluation

Both partners must be evaluated simultaneously rather than sequentially, as couple infertility involves male factors in over 50% of cases. 1, 2 The timeline matters: if the female partner is over 35 years old, evaluation should begin after 6 months of unprotected intercourse rather than waiting 12 months. 3, 2

Male Partner Assessment Components

The reproductive history must specifically document:

• Sexual function parameters: frequency and timing of intercourse, erectile function, ejaculatory function 3, 2
• Prior fertility history: any previous biological children, previous partner pregnancies 3, 4
• Developmental history: history of undescended testes, pubertal timing, childhood illnesses 2, 4
• Medication exposures: testosterone products (which suppress spermatogenesis), anabolic steroids, antidepressants 1
• Environmental and lifestyle factors: heat exposure, smoking, alcohol, occupational exposures 1

Physical examination must assess:

• Testicular volume and consistency: normal volume ≥15 mL; volumes below this suggest testicular dysfunction 5, 2
• Presence and consistency of vas deferens and epididymides: absence suggests congenital bilateral absence of vas deferens 3, 2
• Varicocele presence: palpable varicocele with abnormal semen parameters is treatable 1, 2
• Secondary sex characteristics: body habitus, hair distribution, gynecomastia 3, 2

Semen Analysis Requirements

At least one semen analysis is mandatory for initial evaluation, with proper collection technique critical for validity. 1, 3, 2

Collection Protocol

• Abstinence period: 2-3 days before collection; inadequate abstinence invalidates results 3
• Collection method: masturbation or specialized semen collection condoms 3
• Analysis timing: within one hour of collection to ensure accurate motility assessment 3
• Confirmation testing: if abnormalities detected, repeat analysis at least one month later 3, 2

WHO 2021 Reference Values

Normal parameters include:

• Volume: ≥1.4 mL 2
• Sperm concentration: ≥16 million/mL 5, 2
• Total sperm number: ≥39 million per ejaculate 5, 2
• Progressive motility: ≥30% 5, 2
• Total motility: ≥40-42% 1, 2
• Normal morphology: ≥4% 2

Critical pitfall: A single normal semen analysis does not guarantee fertility, as 25% of infertility cases remain unexplained despite normal conventional parameters. 3 Conversely, one abnormal result cannot definitively diagnose infertility due to substantial biological variation between ejaculates. 3

Advanced Paternal Age Considerations

At age 50, this man has advanced paternal age (≥40 years), which carries specific risks that require counseling. 1, 2

Advanced paternal age increases:

• De novo germline mutations: both intra- and inter-genic mutations 1
• Sperm aneuploidy and chromosomal aberrations 1, 2
• Sperm DNA fragmentation 1
• Offspring health risks: birth defects, chondrodysplasia, schizophrenia, autism 1

Genetic counseling may be considered to discuss the low absolute risk but high relative risk of these outcomes. 1

Specialist Referral Criteria

Men with abnormal semen parameters or presumed male infertility should be evaluated by a male reproductive expert for complete history, physical examination, and directed testing. 1, 2

Mandatory Hormonal Evaluation Triggers

Order FSH and testosterone if:

• Sperm concentration <10 million/mL 3, 2
• Oligozoospermia or azoospermia 1, 2
• Impaired libido or erectile dysfunction 1, 2
• Clinical findings suggesting endocrinopathy 3, 2

Genetic Testing Indications

Order karyotype and Y-chromosome microdeletion testing if:

• Severe oligospermia (<5 million/mL) 3, 2
• Azoospermia 3, 2

Treatment Pathways Based on Findings

If Normal Semen Parameters

• Proceed with timed intercourse: optimize frequency and timing 2
• Address modifiable risk factors: diet (lower fat, more fruits/vegetables), smoking cessation, avoid heat exposure, medication review 1, 5
• Female partner evaluation: female factors account for the other 50% of couple infertility 1

If Treatable Male Factor Identified

• Varicocele with abnormal parameters: varicocelectomy improves fertility rates in couples where female partner has good ovarian reserve 1
• Hypogonadotropic hypogonadism: targeted hormonal therapy (NOT testosterone, which suppresses spermatogenesis) 5, 4
• Male accessory gland infections: antibiotic treatment may improve sperm quality 1
• Reversible medication effects: discontinue gonadotoxic agents when possible 1

Absolute contraindication: Testosterone therapy will suppress spermatogenesis and is absolutely contraindicated if fertility is a goal. 5

If Severe Male Factor or Failed Natural Conception

• Assisted reproductive technology (ART): in vitro fertilization with intracytoplasmic sperm injection (ICSI) for severe oligospermia 6, 7
• Surgical sperm extraction: testicular sperm extraction (TESE) for azoospermia 1, 7
• Sperm cryopreservation: preserve fertility potential before any gonadotoxic treatments 1

Health Implications Beyond Fertility

Infertile men with abnormal semen parameters have higher rates of testicular cancer, overall cancer, and increased mortality compared to fertile men. 1, 2, 8 This fertility evaluation represents an opportunity to improve overall health beyond immediate reproductive goals. 8

Men with specific identifiable causes of infertility should be informed of relevant associated health conditions, including:

• Genetic conditions: Klinefelter syndrome, Y-chromosome microdeletions 1, 2
• Chronic comorbidities: metabolic disease, cardiovascular disease 1, 8
• Future disease risk: cancer surveillance, metabolic screening 8

Critical Pitfalls to Avoid

• Do not assume prior fertility guarantees current fertility: semen parameters change over time due to aging, illness, medications, and lifestyle factors 3
• Do not start testosterone therapy without determining fertility intentions: this causes irreversible suppression of spermatogenesis during treatment 5
• Do not rely on home sperm tests for diagnosis: these are screening tools only and cannot replace comprehensive laboratory semen analysis 3
• Do not proceed with ART without proper male evaluation: most cases of male infertility can be treated and reversed by medical or surgical interventions, and natural pregnancy should be the goal 6
• Do not evaluate the male partner in isolation: concurrent female partner evaluation is essential, as female fecundity determines whether ART is required 1, 9