I will examine the meaning of ‘natural' as perceived by Clinical Embryologists (CEs) within their daily work at In Vitro Fertilization (IVF) clinics. I will describe two main protocols for egg fertilization, a tension between the bio-medical literature and the CE's preference, and I will argue that certain moral and epistemological values can – at least partly – explain the CEs preference. 

CEs use mainly two protocols to achieve fertilization: insemination and intracytoplasmic sperm injection (ICSI). In insemination one egg and about fifty thousand sperms are incubated together in a petri-dish. In ICSI one sperm is selected and is injected into an egg. Since ICSI gives, according to bio-medical literature, a higher rate of fertilization we would expect CEs to prefer ICSI. But my interviews with CEs show that in cases not involving male infertility they would rather use insemination. 

One explanation of their preference rests on the tension between choice, coercion and social responsibility. Seemingly, the insemination protocol follows a process of natural selection where the “egg chooses” the “best sperm,” as one CE noted. But with ICSI a CE chooses a sperm, based on its morphological appearance alone “forcing it on the egg where the egg has no possibility to resist.” Hence, the responsibility for fertilization passes from the egg to the CE and this may explain why they would like to avoid ICSI. Additionally, CEs are concerned whether they are passing-on infertility to the next generation, something that would not occur if the protocol used was insemination so that regeneration is left in the hands of “nature.”