Hhmmm, seems the higher incidence of boys we found in here, is not just coincidence....:
Sex Ratio of Infants Born as a Result of Fertility Treatment
Media Release 20-06-2006
Young Australian scientist has presented significant new research on the sex ratio of children born as a result of the two most common forms of fertility treatment In Vitro Fertilisation (IVF) and Intra Cytoplasmic Sperm Injection (ICSI) at this week’s 22nd annual meeting of the European Society of Human Reproduction and Embryology.
“We found that embryos, conceived using the IVF technique, and grown for a longer period of time, have a higher chance of being a boy,” said Jean Scott, embryologist, IVFAustralia, invited speaker at the conference.
“The purpose of this study was to examine live birth sex ratios for assisted reproductive technology pregnancies following blastocyst culture, where the embryo is grown for 5 days before being transferred back to the woman,” she explained.
If a couple has IVF, not ICSI, and the embryo is grown to a blastocyst before being transferred back to the woman, there is a 56 per cent chance the child will be a boy.
Ms Scott explained that the reason for this is that today we predominantly undertake single embryo transfers, and as male embryos grow slightly faster than female embryos, the embryo selected at first transfer is more likely to be a boy.
“This study is reporting on results of two fertility treatments most commonly undertaken across the country. We do not believe this research will influence a change in treatments or affect the future number of girls and boys being born as a result of assisted conception,” said A/Professor Peter Illingworth, Medical Director IVFAustralia.
”We will provide our patients with information about this effect and that this approach will give them a slightly higher chance of having a boy. However, the most important aspect is that fertility teams will continue to select the most advanced appearing embryos to give a couple the optimal chance of conceiving a baby,” he said.
The study also reviewed a number of possible causes for shifts in sex ratios including media batch variation, individual patient embryonic development, stage of Day 5 embryo transferred and maternal age.
There was a significant difference in sex ratios when analysing individual patient blastocyst developmental rates. It appears that overall slower developmental rates were associated with a higher incidence of females being born and faster developmental rates with more males.
Neither maternal age nor media batch variability contributed greatly to the shift in sex ratios observed.
