distinction based on the method of conception: the biological relationship between the father and the child and the reason for the pregnancy having been achieved will be the same whether the child was conceived naturally or by artificial means, but the legal position has been different. In some countries and in some situations, sperm donors may be legally liable for any child they produce, but with NI the legal risk of paternity for a donor has always been absolute. Natural insemination donors will therefore often donate without revealing their identity. A case in 2019 in the Canadian province of Ontario has, however thrown doubt on this position. That case held that where the parties agreed in advance of the conception that the resulting child would not be the legal responsibility of the man, the courts would uphold that agreement. The court held that the method of conception was irrelevant: it was the purpose of it which mattered. Where an artificial means of conception is used, the reproductive integrity of the recipient woman will not be preserved, and the purpose of preserving sexual integrity by employing artificial means of insemination will not over-ride this effect. Many private sperm donors now offer both natural and artificial insemination, or they may offer natural insemination after attempts to achieve conception by artificial insemination have failed. Some sperm donors are influenced by the fact that a woman who is not the donor's usual sexual partner will carry his child whatever the means of conception, and that the actual method by which his sperm is introduced into the woman's body is of a lesser consideration than this fact. Women may seek natural insemination for various reasons including the desire by them for a "natural" conception. Natural insemination by a donor usually avoids the need for costly medical procedures that may require the intervention of third parties. It may lack some of the safety precautions and screenings usually built into the artificial insemination process but proponents claim that it produces higher pregnancy rates. A more 'natural' conception does not involve the intervention and intrusion of third parties. However, it has not been medically proved that natural insemination has an increased chance of pregnancy. NI is generally only carried out at the female's fertile time, as with other methods of insemination, in order to achieve the best chances of a pregnancy. A variation of NI is PI, or