Brona McVittie reports :: July 2006

Women like younger men, but recent advances in stem cell research mean that potential fathers need not have yet reached sexual maturity. In a Developmental Cell paper, Karim Nayernia (Newcastle University) describes how his team created sperm from embryonic stem cells. Using IVF the researchers were able to impregnate females and produce offspring. Mice developed to adulthood but either grew too large or too small owing to abnormal imprinting.