Study summary

An AI system found sperm that technicians could not, leading to a pregnancy

STAR first pregnancy · One couple · Reported 2025; Lancet letter October 2025

What was tested

STAR (Sperm Tracking and Recovery), built at Columbia University, images a semen sample millions of times, uses AI to spot rare sperm, and a microfluidic chip to pull them out unharmed.

What they found

• The couple had tried for 18 years. Technicians had searched a sample for two days without finding sperm.
• The system found sperm within about an hour. Reports of the exact number differ.
• The researchers describe it as showing the method is feasible, not how often it works.
• At the time of the reports it was offered at one clinic.

What it means

The first sign that some men labeled as having no sperm have a few that better search tools can find. Success rates across many men have not been published.