From the u . s . comes research that the common practice of storing fertilised embryos can prooke genetic changes that may deelop into mental and behaioural disorders later in life ; from canada come claims that if can increase some birth defects tenfold ; while from denmark a study of young men finds those conceied through fertility treatment are 50 per cent more likely to be infertile themseles 来自美国的研究显示，保存受精胚胎的常用程序可引起遗传物质的改变，这些改变在生命后期会引起精神和行为疾病；加拿大的研究宣称if可使出生缺陷增加十倍；同时丹麦有关青年男性的研究显示，那些经过生育治疗受孕出生的男性本身的不育率要升高50 。
