To exclude the effects of hormonal treatment and the effect of freezing of untransferred embryos on the statistics, ShermanJ. Silber, Keiichi Kato et al, studied the intrinsic fertility of human oocytes through a large retrospective study of a natural cycle single embryo transfer population, using live birth rate per egg as an observation. A total of 14,185 oocytes from natural cycles were used to obtain 1,913 live births from single embryo transfer. Statistics showed that the live birth rate per egg varied significantly with age. The live birth rate per oocyte varied minimally up to age 34 (only 10% were lost throughout this period), with a single egg or birth rate of 26% up to age 35. However, steep (near linear) losses then begin, with a 10% annual decline in live birth rate between 34 and 42 years of age, a 20% decline at 36 years of age, a 90% decline at 42 years of age, and a live birth rate of only 4% per egg, with the decline plateauing after 43 years of age, however, with live birth rates of only 3% per egg at 45 years of age, only 2% at 46 years of age, and even less than 1% at 47 years of age. Through the above data, we can deeply appreciate that time is not waiting for people, and we need to catch up with the pace of time if we want to have a healthy and lovely baby.